Organic light-emitting device and apparatus including the same

ABSTRACT

An organic light-emitting device includes a first electrode; a second electrode facing the first electrode; and an organic layer disposed between the first electrode and the second electrode and including a first emission layer and a second emission layer; wherein the first emission layer is located closer to the first electrode than the second emission layer and includes a first hole transport host, a first electron transport host, and a first phosphorescent dopant, and, in the first emission layer, an amount of the first hole transport host is greater than an amount of the first electron transport host, the second emission layer includes a second hole transport host, a second electron transport host, and a second phosphorescent dopant, and, in the second emission layer, an amount of the second electron transport host is greater than an amount of the second hole transport host, and the first emission layer and the second emission layer are configured to emit light of substantially the same color.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean PatentApplication No. 10-2019-0146174, filed on Nov. 14, 2019, which isincorporated by reference for all purposes as if fully set forth herein.

BACKGROUND Field

Exemplary implementations of the invention relate generally to displaydevices and, more particularly, to an organic light-emitting device andan apparatus including the same.

Discussion of the Background

Organic light-emitting devices are self-emission devices that producefull-color images, and also have wide viewing angles, high contrastratios, short response times, and excellent characteristics in terms ofbrightness, driving voltage, and response speed, compared to devices inthe art.

An example of the organic light-emitting devices may include a firstelectrode located on a substrate, and a hole transport region, anemission layer, an electron transport region, and a second electrode,which are sequentially located on the first electrode. Holes providedfrom the first electrode may move toward the emission layer through thehole transport region, and electrons provided from the second electrodemay move toward the emission layer through the electron transportregion. Carriers, such as holes and electrons, recombine in the emissionlayer to produce excitons.

According to electron spin statistics, singlet excitons and tripletexcitons are formed in a ratio of 1:3. Regarding these excitons, thetransition between singlet excitons and triplet excitons occurs byinter-system crossing (ISC) or triplet-triplet fusion (TTF). In the caseof devices using fluorescent emitters, light is formed while the singletexcitons transition from the excited state to the ground state, and inthe case of devices using phosphorescent emitters, light is formed whilethe triplet excitons transition from the excited state to the groundstate. However, many existing organic light-emitting devices suffer fromreduced lifespans during operation.

The above information disclosed in this Background section is only forunderstanding of the background of the inventive concepts, and,therefore, it may contain information that does not constitute priorart.

SUMMARY

Applicant discovered that by combining emission layers of organiclight-emitting devices with different attributes unexpected synergisticimprovements in lifespan are obtained.

Organic emitting-light devices and apparatuses including the sameconstructed according to the principles and exemplary implementations ofthe invention have long lifespans. For example, the emission layer of anorganic light-emitting device composed of one or more layers of certaincompounds, particularly a first emission layer having an amount of afirst hole transport host greater than the amount of the first electrontransport host, and a second emission layer having a second electrontransport host greater than an amount of the second hole transport host,where the first emission layer and the second emission layer emit lightof the same color, exhibit improved lifespan.

Additional features of the inventive concepts will be set forth in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the inventive concepts.

According to one aspect of the invention, an organic light-emittingdevice includes: a first electrode; a second electrode facing the firstelectrode; and an organic layer disposed between the first electrode andthe second electrode and including a first emission layer and a secondemission layer; wherein the first emission layer is located closer tothe first electrode than the second emission layer and includes a firsthole transport host, a first electron transport host, and a firstphosphorescent dopant, and, in the first emission layer, an amount ofthe first hole transport host is greater than an amount of the firstelectron transport host, the second emission layer includes a secondhole transport host, a second electron transport host, and a secondphosphorescent dopant, and, in the second emission layer, an amount ofthe second electron transport host is greater than an amount of thesecond hole transport host, and the first emission layer and the secondemission layer are configured to emit light of substantially the samecolor.

The first hole transport host and the second hole transport host mayeach, independently from one another, be at least one of a compoundrepresented by Formula 1:

the first electron transport host and the second electron transport hostare each, independently from one another, a compound represented byFormula 2:

wherein, in Formula 1 and Formula 2,Y₁ is a single bond, —O—, —S—, —C(R₂₄)(R₂₅)—, —N(R₂₄)—, —Si(R₂₄)(R₂₅)—,—C(═O)—, —S(═O)₂—, —B(R₂₄)—, —P(R₂₄)—, or —P(═O)(R₂₄)(R₂₅)—;k1 is 0 or 1;CY₂₁ and CY₂₂ are each, independently from one another, a C₅-C₆₀carbocyclic group or a C₁-C₆₀ heterocyclic group;X₃₁ is N or C[(L₃₄)_(a34)-(R₃₁)], X₃₂ is N or C[(L₃₅)_(a35)-(R₃₂)], andX₃₃ is N or C[(L₃₆)_(a36)-(R₃₃)];L₂₁ to L₂₃ and L₃₁ to L₃₆ are each, independently from one another, asubstituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substitutedor unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted orunsubstituted C₃-C₁₀ cycloalkenylene group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted orunsubstituted C₆-C₆₀ arylene group, a substituted or unsubstitutedC₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalentnon-aromatic fused polycyclic group, or a substituted or unsubstituteddivalent non-aromatic fused heteropolycyclic group;a21 to a23 and a31 to a36 are each, independently from one another, aninteger from 0 to 5; Ar₂₁ to Ar₂₃ and Ar₃₁ to Ar₃₃ are each,independently from one another, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic fused polycyclic group, or a substituted orunsubstituted monovalent non-aromatic fused heteropolycyclic group;b21 to b23 and b31 to b33 are each, independently from one another, aninteger from 1 to 8;R₂₁ to R₂₂, R₂₄ to R₂₅, and R₃₁ to R₃₃ are each, independently from oneanother, hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a substituted or unsubstituted C₁-C₆₀ alkyl group, asubstituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted orunsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstitutedC₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkylgroup, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted C₁-C₆₀ heteroaryloxy group, a substituted or unsubstitutedC₁-C₆₀ heteroarylthio group, a substituted or unsubstituted monovalentnon-aromatic fused polycyclic group, a substituted or unsubstitutedmonovalent non-aromatic fused heteropolycyclic group, —Si(Q₁)(Q₂)(Q₃),—N(Q₁)(Q₂), —B(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)₂(Q₁) and —P(═O)(Q₁)(Q₂);c21 and c22 are each, independently from one another, an integer from 1to 8;n21 and n22 are each, independently from one another, an integer from 1to 8;at least two of Ar₂₁ to Ar₂₃ and R₂₁ to R₂₂ are optionally linked toeach other to form a substituted or unsubstituted C₅-C₆₀ carbocyclicgroup or a substituted or unsubstituted C₁-C₆₀ heterocyclic group;at least two of Ar₃₁ to Ar₃₃ and R₃₁ to R₃₃ are optionally linked toeach other to form a substituted or unsubstituted C₅-C₆₀ carbocyclicgroup or a substituted or unsubstituted C₁-C₆₀ heterocyclic group; andat least one substituent of the substituted C₃-C₁₀ cycloalkylene group,the substituted C₁-C₁₀ heterocycloalkylene group, the substituted C₃-C₁₀cycloalkenylene group, the substituted C₁-C₁₀ heterocycloalkenylenegroup, the substituted C₆-C₆₀ arylene group, the substituted C₁-C₆₀heteroarylene group, the substituted divalent non-aromatic fusedpolycyclic group, the substituted divalent non-aromatic fusedheteropolycyclic group, the substituted C₅-C₆₀ carbocyclic group, thesubstituted C₁-C₆₀ heterocyclic group, the substituted C₁-C₆₀ alkylgroup, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substitutedC₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group,the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, thesubstituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group,the substituted C₁-C₆₀ heteroaryl group, the substituted C₁-C₆₀heteroaryloxy group, the substituted C₁-C₆₀ heteroarylthio group, thesubstituted monovalent non-aromatic fused polycyclic group, and thesubstituted monovalent non-aromatic fused heteropolycyclic group is:deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and aC₁-C₆₀ alkoxy group;a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each, independently from one another,substituted with at least one of deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic fused polycyclic group, a monovalent non-aromatic fusedheteropolycyclic group, —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂),—C(═O)(Q₁₁), —S(═O)₂(Q₁₁), and —P(═O)(Q₁₁)(Q₁₂);a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic fused polycyclic group, anda monovalent non-aromatic fused heteropolycyclic group, each,independently from one another, optionally substituted with at least oneof deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkylgroup, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, aC₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, aC₁-C₆₀ heteroaryl group, a monovalent non-aromatic fused polycyclicgroup, a monovalent non-aromatic fused heteropolycyclic group,—Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁),—S(═O)₂(Q₂₁), and —P(═O)(Q₂₁)(Q₂₂); and—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂);wherein Q₁ to Q₃, Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ are each,independently from one another, hydrogen, deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic fused polycyclic group, amonovalent non-aromatic fused heteropolycyclic group, a biphenyl group,and a terphenyl group.

The first hole transport host and the second hole transport host may besubstantially identical to each other.

The first electron transport host and the second electron transport hostmay be substantially identical to each other.

The first emission layer and the second emission layer may each beconfigured to emit blue light having a maximum emission wavelength ofabout 400 nm to about 500 nm.

The first phosphorescent dopant and the second phosphorescent dopant maybe substantially identical to each other.

The at least one of the first emission layer and the second emissionlayer may further include at least one of a fluorescence dopant and adelayed fluorescence dopant.

The organic layer may further include a third emission layer disposedbetween the first emission layer and the second emission layer, and thethird emission layer may include a third hole transport host, a thirdelectron transport host, and a third phosphorescent dopant.

The amount of the first hole transport host in the first emission layermay be greater than an amount of the third hole transport host in thethird emission layer, and the amount of the third hole transport host inthe third emission layer may be greater than the amount of the secondhole transport host in the second emission layer.

The amount of the second electron transport host in the second emissionlayer may be greater than an amount of the third electron transport hostin the third emission layer, and the amount of the third electrontransport host in the third emission layer may be greater than theamount of the first electron transport host in the first emission layer.

The third hole transport host and the third electron transport host ofthe third emission layer may have a weight ratio in the range of about4:6 to about 6:4.

The first hole transport host, the second hole transport host, and thethird hole transport host may be substantially identical to each other.

The first electron transport host, the second electron transport host,and the third electron transport host may be substantially identical toeach other.

The first phosphorescent dopant, the second phosphorescent dopant, andthe third phosphorescent dopant may be substantially identical to eachother.

The first electrode may be an anode; the second electrode may be acathode; and the organic layer further may include a hole transportregion disposed between the first electrode and an emission layer (e.g.the first emission layer) and an electron transport region disposedbetween the emission layer (e.g. the second emission layer) and thesecond electrode.

The hole transport region may include at least one of a hole injectionlayer, a hole transport layer, a buffer layer, an emission auxiliarylayer, and an electron blocking layer, and the electron transport regionmay include at least one of a hole blocking layer, a buffer layer, anelectron control layer, an electron transport layer, and an electroninjection layer.

The hole transport region may include a p-dopant having a lowestunoccupied molecular orbital energy level of less than about −3.5 eV.

The electron transport region may include a hole blocking layerincluding a hole blocking material; the hole blocking layer directlycontacts the second emission layer; and the hole blocking material maybe substantially the same as the second electron transport host.

The electron transport region may include a metal-containing material.

According to another aspect of the invention, an organic light-emittingdevice includes: a first electrode; a second electrode facing the firstelectrode; and an organic layer disposed between the first electrode andthe second electrode and including an emission layer, having a firstemission area and the second emission area; wherein, in the emissionlayer, the first emission area is located closer to the first electrodethan the second emission area; each of the first emission area and thesecond emission area includes a hole transport host, an electrontransport host, and a phosphorescent dopant; an amount of the holetransport host in the first emission area is greater than an amount ofthe electron transport host in the first emission area;

an amount of the electron transport host in the second emission area isgreater than an amount of the hole transport host in the second emissionarea; andthe phosphorescent dopant is an organometallic compound represented byFormula 4 or 5:

wherein, the variables are defined herein.

The emission layer may be configured to emit blue light having a maximumemission wavelength of about 400 nm to about 500 nm.

The amount of the hole transport host in an emission layer may graduallydecrease from the first emission area toward the second emission area,and the amount of the electron transport host in the emission layergradually may increase from the first emission area toward the secondemission area.

The first electrode may be an anode, the second electrode may be acathode, the organic layer further may include a hole transport regiondisposed between the first electrode and the emission layer and anelectron transport region disposed between the emission layer and thesecond electrode, the hole transport region may include at least one ofa hole injection layer, a hole transport layer, a buffer layer, anemission auxiliary layer, and an electron blocking layer, and theelectron transport region may include at least one of a hole blockinglayer, a buffer layer, an electron control layer, an electron transportlayer, and an electron injection layer.

The hole transport region may include a p-dopant having a lowestunoccupied molecular orbital energy level of less than about −3.5 eV.

The electron transport region may include the hole blocking layerincluding a hole blocking material; the hole blocking layer may directlycontact the emission layer; and the hole blocking material may besubstantially identical to the hole transport host.

The electron transport region may include a metal-containing material.

An apparatus may include a thin-film transistor including a sourceelectrode, a drain electrode, and an activation layer; and an organiclight-emitting device as described above; wherein the first electrode ofthe organic light-emitting device may be electrically connected with oneof the source electrode and the drain electrode of the thin-filmtransistor.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate exemplary embodiments of theinvention, and together with the description serve to explain theinventive concepts.

FIG. 1 is a schematic cross-sectional diagram of an exemplary embodimentof an organic light-emitting device constructed according to principlesof the invention.

FIG. 2 is a schematic cross-sectional diagram of another exemplaryembodiment of an organic light-emitting device constructed according toprinciples of the invention.

FIG. 3 is a schematic cross-sectional diagram of yet another exemplaryembodiment of an organic light-emitting device constructed according toprinciples of the invention.

FIG. 4 is a schematic diagram of an exemplary embodiment of an apparatuscontaining an organic light-emitting device constructed according toprinciples of the invention.

DETAILED DESCRIPTION

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of various exemplary embodiments or implementations of theinvention. As used herein “embodiments” and “implementations” areinterchangeable words that are non-limiting examples of devices ormethods employing one or more of the inventive concepts disclosedherein. It is apparent, however, that various exemplary embodiments maybe practiced without these specific details or with one or moreequivalent arrangements. In other instances, well-known structures anddevices are shown in block diagram form in order to avoid unnecessarilyobscuring various exemplary embodiments. Further, various exemplaryembodiments may be different, but do not have to be exclusive. Forexample, specific shapes, configurations, and characteristics of anexemplary embodiment may be used or implemented in another exemplaryembodiment without departing from the inventive concepts.

Unless otherwise specified, the illustrated exemplary embodiments are tobe understood as providing exemplary features of varying detail of someways in which the inventive concepts may be implemented in practice.Therefore, unless otherwise specified, the features, components,modules, layers, films, panels, regions, and/or aspects, etc.(hereinafter individually or collectively referred to as “elements”), ofthe various embodiments may be otherwise combined, separated,interchanged, and/or rearranged without departing from the inventiveconcepts.

The use of cross-hatching and/or shading in the accompanying drawings isgenerally provided to clarify boundaries between adjacent elements. Assuch, neither the presence nor the absence of cross-hatching or shadingconveys or indicates any preference or requirement for particularmaterials, material properties, dimensions, proportions, commonalitiesbetween illustrated elements, and/or any other characteristic,attribute, property, etc., of the elements, unless specified. Further,in the accompanying drawings, the size and relative sizes of elementsmay be exaggerated for clarity and/or descriptive purposes. When anexemplary embodiment may be implemented differently, a specific processorder may be performed differently from the described order. Forexample, two consecutively described processes may be performedsubstantially at the same time or performed in an order opposite to thedescribed order. Also, like reference numerals denote like elements.

When an element, such as a layer, is referred to as being “on,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, connected to, or coupled to the other element or layer orintervening elements or layers may be present. When, however, an elementor layer is referred to as being “directly on,” “directly connected to,”or “directly coupled to” another element or layer, there are nointervening elements or layers present. To this end, the term“connected” may refer to physical, electrical, and/or fluid connection,with or without intervening elements. Further, the D1-axis, the D2-axis,and the D3-axis are not limited to three axes of a rectangularcoordinate system, such as the x, y, and z-axes, and may be interpretedin a broader sense. For example, the D1-axis, the D2-axis, and theD3-axis may be perpendicular to one another, or may represent differentdirections that are not perpendicular to one another. For the purposesof this disclosure, “at least one of X, Y, and Z” and “at least oneselected from the group consisting of X, Y, and Z” may be construed as Xonly, Y only, Z only, or any combination of two or more of X, Y, and Z,such as, for instance, XYZ, XYY, YZ, and ZZ. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

Although the terms “first,” “second,” etc. may be used herein todescribe various types of elements, these elements should not be limitedby these terms. These terms are used to distinguish one element fromanother element. Thus, a first element discussed below could be termed asecond element without departing from the teachings of the disclosure.

Spatially relative terms, such as “beneath,” “below,” “under,” “lower,”“above,” “upper,” “over,” “higher,” “side” (e.g., as in “sidewall”), andthe like, may be used herein for descriptive purposes, and, thereby, todescribe one elements relationship to another element(s) as illustratedin the drawings. Spatially relative terms are intended to encompassdifferent orientations of an apparatus in use, operation, and/ormanufacture in addition to the orientation depicted in the drawings. Forexample, if the apparatus in the drawings is turned over, elementsdescribed as “below” or “beneath” other elements or features would thenbe oriented “above” the other elements or features. Thus, the exemplaryterm “below” can encompass both an orientation of above and below.Furthermore, the apparatus may be otherwise oriented (e.g., rotated 90degrees or at other orientations), and, as such, the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments and is not intended to be limiting. As used herein, thesingular forms, “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. Moreover,the terms “comprises,” “comprising,” “includes,” and/or “including,”when used in this specification, specify the presence of statedfeatures, integers, steps, operations, elements, components, and/orgroups thereof, but do not preclude the presence or addition of one ormore other features, integers, steps, operations, elements, components,and/or groups thereof. It is also noted that, as used herein, the terms“substantially,” “about,” and other similar terms, are used as terms ofapproximation and not as terms of degree, and, as such, are utilized toaccount for inherent deviations in measured, calculated, and/or providedvalues that would be recognized by one of ordinary skill in the art.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure is a part. Terms,such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and should not be interpreted in anidealized or overly formal sense, unless expressly so defined herein.

The term “organic layer” as used herein refers to a single layer and/ora plurality of layers located between the first electrode and the secondelectrode of an organic light-emitting device. A material included inthe “organic layer” is not limited to an organic material.

The expression “(an organic layer) includes a compound represented byFormula “A” (N is an integer) as used herein may include a case in whichan organic layer includes one compound of Formula N or two or moredifferent compounds of Formula N.

FIG. 1 is a schematic cross-sectional diagram of an exemplary embodimentof an organic light-emitting device constructed according to principlesof the invention.

Referring to FIG. 1, the organic light-emitting device 10 includes afirst electrode 110; a second electrode 190 facing the first electrode110; and an organic layer 150 including an emission layer 130. Theemission layer 130 can have sublayers, such as a first emission layer131 and a second emission layer 132, located between the first electrode110 and the second electrode 190, wherein the first emission layer 131is located closer to the first electrode 110 than the second emissionlayer 132.

The first emission layer 131 includes a first hole transport host, afirst electron transport host, and a first phosphorescent dopant, and,in the first emission layer 131, the amount of the first hole transporthost is greater than the amount of the first electron transport host.

The second emission layer 132 includes a second hole transport host, asecond electron transport host, and a second phosphorescent dopant, and,in the second emission layer 132, the amount of the second electrontransport host is greater than the amount of the second hole transporthost.

The emission layer 130 of the organic light-emitting device 10 includesthe first emission layer 131 and the second emission layer 132, and eachof the first emission layer 131 and the second emission layer 132includes the hole transport host and electron transport host, each ofwhich ratio with respect to the phosphorescent dopant is controlled.Accordingly, in the emission layer 130 of the organic light-emittingdevice 10, the balance between holes and electrons is controlled, andthus, the hole-electron recombination region is maintained within theemission layer 130. Therefore, exciton-polaron quenching is prevented,and the concentration of excitons in the emission layer 130 isappropriately controlled to prevent exciton-exciton quenching. As aresult, the lifespan characteristics of the organic light-emittingdevice 10 may be significantly improved.

The first emission layer 131 and the second emission layer 132 emitlight of the same color.

The first electrode 110 may be formed by depositing or sputtering amaterial for forming the first electrode 110 on a substrate. Thematerial for forming the first electrode 110 may be selected frommaterials with a high work function to facilitate hole injection.

The first electrode 110 may be a reflective electrode, asemi-transmissive electrode, or a transmissive electrode. To form atransmissive electrode, a material for forming a first electrode may beselected from an indium tin oxide (ITO), an indium zinc oxide (IZO), atin oxide (SnO₂), a zinc oxide (ZnO), and any combinations thereof, butexemplary embodiments are not limited thereto. In one or more exemplaryembodiments, to form a semi-transmissive electrode or a reflectiveelectrode, a material for forming a first electrode may be selected frommagnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al—Li),calcium (Ca), magnesium-indium (Mg—In), magnesium-silver (Mg—Ag), andany combinations thereof, but the exemplary embodiments are not limitedthereto.

The first electrode 110 may have a single-layered structure, or amulti-layered structure including two or more layers. For example, thefirst electrode 110 may have a three-layered structure of an ITO/Ag/ITO,but the structure of the first electrode 110 is not limited thereto.

The organic layer 150 is located on the first electrode 110. Asdescribed above, the organic layer 150 includes the emission layer 130,and the emission layer 130 includes the first emission layer 131 and thesecond emission layer 132. The organic layer 150 may further include ahole transport region between the first electrode 110 and the firstemission layer 131 and an electron transport region between the secondemission layer 132 and the second electrode 190.

The hole transport region may have i) a single-layered structureincluding a single layer including a single material, ii) asingle-layered structure including a single layer including a pluralityof different materials, or iii) a multi-layered structure having aplurality of layers including a plurality of different materials.

Referring to FIG. 1B, the hole transport region may include at least onelayer selected from a hole injection layer, a hole transport layer, anemission auxiliary layer, and an electron blocking layer.

For example, the hole transport region may have a single-layeredstructure including a single layer including a plurality of differentmaterials, or a multi-layered structure having a hole injectionlayer/hole transport layer structure, a hole injection layer/holetransport layer/emission auxiliary layer structure, a hole injectionlayer/emission auxiliary layer structure, a hole transportlayer/emission auxiliary layer structure, or a hole injection layer/holetransport layer/electron blocking layer structure, wherein for eachstructure, constituting layers are sequentially stacked from the firstelectrode 110 in this stated order, but the structure of the holetransport region is not limited thereto.

The hole transport region may include at least one compound selectedfrom 4,4′,4″-tris[phenyl(m-tolyl)amino]triphenylamine (m-MTDATA), 1-N,1-N-bis[4-(diphenylamino)phenyl]-4-N,4-N-diphenylbenzene-1,4-diamine(TDATA), 4,4′,4″-tris[2-naphthyl(phenyl)amino]triphenylamine (2-TNATA),N,N′-di(naphtalene-1-yl)-N,N′-diphenyl-benzidine (NPB orNPD),N4,N4′-di(naphthalen-2-yl)-N4,N4′-diphenyl-[1,1′-biphenyl]-4,4′-diamine(P—NPB),N,N′-bis(3-methylphenyl)-N,N′-diphenyl-[1,1′-biphenyl]-4,4′-diamine(TPD),4(N,N′-bis(3-methylphenyl)-N,N′-diphenyl-9,9-spirobifluorene-2,7-diamine(spiro-TPD), 2,7-bis[N-(l-naphthyl)anilino]-9,9′-spirobi[9H-fluorene](spiro-NPB),2,2′-dimethyl-N,N′-di-[(l-naphthyl)-N,N′-diphenyl]-1,1′-biphenyl-4,4′-diamine(methylated NPB), 4,4′-cyclohexylidenebis[N,N-bis(4-methylphenyl)benzenamine] (TAPC),4,4′-bis[N,N′-(3-tolyl)amino]-3,3′-dimethylbiphenyl (HMTPD),4,4′,4″-tris(N-carbazolyl)triphenylamine (TCTA),polyaniline/dodecylbenzenesulfonic acid (PANI/DBSA),poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonate) (PEDOT/PSS),polyaniline/camphor sulfonic acid (PANI/CSA),polyaniline/poly(4-styrenesulfonate) (PANI/PSS),9-(4-tert-butylphenyl)-3,6-bis(triphenylsilyl)-9H-carbazole (CzSi),triphenylamine-based compounds such as4,4′,4″-tris(carbazol-9-yl)triphenylamine (TCTA), a compound representedby Formula 201, and a compound represented by Formula 202:

In Formulae 201 and 202,

L₂₀₁ to L₂₀₄ may each independently be selected from a substituted orunsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group,

L₂₀₅ may be selected from *—O—*′, *—S—*′, *—N(Q₂₀₁)-*′, a substituted orunsubstituted C₁-C₂₀ alkylene group, a substituted or unsubstitutedC₂-C₂₀ alkenylene group, a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group,

xa1 to xa4 may each independently be an integer from 0 to 3,

xa5 may be an integer from 1 to 10, and

R₂₀₁ to R₂₀₄ and Q₂₀₁ may each independently be selected from asubstituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted orunsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀aryl group, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic condensed polycyclic group, and a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group.

In one exemplary embodiment, in Formula 202, R₂₀₁ and R₂₀₂ mayoptionally be linked to each other via a single bond, adimethyl-methylene group, or a diphenyl-methylene group, and R₂₀₃ andR₂₀₄ may optionally be linked to each other via a single bond, adimethyl-methylene group, or a diphenyl-methylene group.

In one exemplary embodiment, in Formulae 201 and 202,

L₂₀₁ to L₂₀₅ may each independently be selected from:

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anindacenylene group, an acenaphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenalenylene group, a phenanthrenylenegroup, an anthracenylene group, a fluoranthenylene group, atriphenylenylene group, a pyrenylene group, a chrysenylene group, anaphthacenylene group, a picenylene group, a perylenylene group, apentaphenylene group, a hexacenylene group, a pentacenylene group, arubicenylene group, a coronenylene group, an ovalenylene group, athiophenylene group, a furanylene group, a carbazolylene group, anindolylene group, an isoindolylene group, a benzofuranylene group, abenzothiophenylene group, a dibenzofuranylene group, adibenzothiophenylene group, a benzocarbazolylene group, adibenzocarbazolylene group, a dibenzosilolylene group, and apyridinylene group; and

a phenylene group, a pentalenylene group, an indenylene group, anaphthylene group, an azulenylene group, a heptalenylene group, anindacenylene group, an acenaphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenalenylene group, a phenanthrenylenegroup, an anthracenylene group, a fluoranthenylene group, atriphenylenylene group, a pyrenylene group, a chrysenylene group, anaphthacenylene group, a picenylene group, a perylenylene group, apentaphenylene group, a hexacenylene group, a pentacenylene group, arubicenylene group, a coronenylene group, an ovalenylene group, athiophenylene group, a furanylene group, a carbazolylene group, anindolylene group, an isoindolylene group, a benzofuranylene group, abenzothiophenylene group, a dibenzofuranylene group, adibenzothiophenylene group, a benzocarbazolylene group, adibenzocarbazolylene group, a dibenzosilolylene group, and apyridinylene group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₁₀alkyl group, a C₁-C₁₀ alkoxy group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group,a phenyl group, a biphenyl group, a terphenyl group, a phenyl groupsubstituted with a C₁-C₁₀ alkyl group, a phenyl group substituted with—F, a pentalenyl group, an indenyl group, a naphthyl group, an azulenylgroup, a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, athiophenyl group, a furanyl group, a carbazolyl group, an indolyl group,an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinylgroup, —Si(Q₃₁)(Q₃₂)(Q₃₃), and —N(Q₃₁)(Q₃₂),

wherein Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, and a naphthyl group.

In one or more exemplary embodiments, xa1 to xa4 may each independentlybe 0, 1, or 2.

In one or more exemplary embodiments, xa5 may be 1, 2, 3, or 4.

In one or more exemplary embodiments, R₂₀₁ to R₂₀₄ and Q₂₀₁ may eachindependently be selected from: a phenyl group, a biphenyl group, aterphenyl group, a pentalenyl group, an indenyl group, a naphthyl group,an azulenyl group, a heptalenyl group, an indacenyl group, anacenaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenalenyl group, aphenanthrenyl group, an anthracenyl group, a fluoranthenyl group, atriphenylenyl group, a pyrenyl group, a chrysenyl group, a naphthacenylgroup, a picenyl group, a perylenyl group, a pentaphenyl group, ahexacenyl group, a pentacenyl group, a rubicenyl group, a coronenylgroup, an ovalenyl group, a thiophenyl group, a furanyl group, acarbazolyl group, an indolyl group, an isoindolyl group, a benzofuranylgroup, a benzothiophenyl group, a dibenzofuranyl group, adibenzothiophenyl group, a benzocarbazolyl group, a dibenzocarbazolylgroup, a dibenzosilolyl group, and a pyridinyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a pentalenyl group,an indenyl group, a naphthyl group, an azulenyl group, a heptalenylgroup, an indacenyl group, an acenaphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenalenyl group, a phenanthrenyl group, an anthracenyl group,a fluoranthenyl group, a triphenylenyl group, a pyrenyl group, achrysenyl group, a naphthacenyl group, a picenyl group, a perylenylgroup, a pentaphenyl group, a hexacenyl group, a pentacenyl group, arubicenyl group, a coronenyl group, an ovalenyl group, a thiophenylgroup, a furanyl group, a carbazolyl group, an indolyl group, anisoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, and apyridinyl group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₁₀alkyl group, a C₁-C₁₀ alkoxy group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group,a phenyl group, a biphenyl group, a terphenyl group, a phenyl groupsubstituted with a C₁-C₁₀ alkyl group, a phenyl group substituted with—F, a pentalenyl group, an indenyl group, a naphthyl group, an azulenylgroup, a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, athiophenyl group, a furanyl group, a carbazolyl group, an indolyl group,an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, a pyridinylgroup, —Si(Q₃₁)(Q₃₂)(Q₃₃), and —N(Q₃₁)(Q₃₂),

Q₃₁ to Q₃₃ are the same as described above.

In one or more exemplary embodiments, at least one selected from R₂₀₁ toR₂₀₃ in Formula 201 may each independently be selected from:

a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group, adibenzofuranyl group, and a dibenzothiophenyl group; and

a fluorenyl group, a spiro-bifluorenyl group, a carbazolyl group, adibenzofuranyl group, and a dibenzothiophenyl group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, acyclopentyl group, a cyclohexyl group, a cycloheptyl group, acyclopentenyl group, a cyclohexenyl group, a phenyl group, a biphenylgroup, a terphenyl group, a phenyl group substituted with a C₁-C₁₀ alkylgroup, a phenyl group substituted with —F, a naphthyl group, a fluorenylgroup, a spiro-bifluorenyl group, a carbazolyl group, a dibenzofuranylgroup, and a dibenzothiophenyl group, but the exemplary embodiments arenot limited thereto.

In one or more exemplary embodiments, in Formula 202, i) R₂₀₁ and R₂₀₂may be linked to each other via a single bond, and/or ii) R₂₀₃ and R₂₀₄may be linked to each other via a single bond.

In one or more exemplary embodiments, R₂₀₁ to R₂₀₄ in Formula 202 mayeach independently be selected from:

a carbazolyl group; and

a carbazolyl group substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group,a phenyl group, a biphenyl group, a terphenyl group, a phenyl groupsubstituted with a C₁-C₁₀ alkyl group, a phenyl group substituted with—F, a naphthyl group, a fluorenyl group, a spiro-bifluorenyl group, acarbazolyl group, a dibenzofuranyl group, and a dibenzothiophenyl group,

but the exemplary embodiments are not limited thereto.

The compound represented by Formula 201 may be represented by Formula201A below:

In one exemplary embodiment, the compound represented by Formula 201 maybe represented by Formula 201 A(1) below, but the exemplary embodimentsare not limited thereto:

In one or more exemplary embodiments, the compound represented byFormula 201 may be represented by Formula 201 A-1 below, but theexemplary embodiments are not limited thereto:

In one exemplary embodiment, the compound represented by Formula 202 maybe represented by Formula 202A below:

In one or more exemplary embodiments, the compound represented byFormula 202 may be represented by Formula 202A-1 below:

In Formulae 201A, 201A(1), 201A-1, 202A, and 202A-1,

L₂₀₁ to L₂₀₃, xa1 to xa3, xa5, and R₂₀₂ to R₂₀₄ may each be understoodby referring to the corresponding descriptions thereof presented herein,

R₂₁₁ and R₂₁₂ may each be understood by referring to the descriptionsprovided in connection with R₂₀₃ herein, and

R₂₁₃ to R₂₁₇ may each independently be selected from hydrogen,deuterium, —F, —C₁, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a cyclopentyl group, a cyclohexylgroup, a cycloheptyl group, a cyclopentenyl group, a cyclohexenyl group,a phenyl group, a biphenyl group, a terphenyl group, a phenyl groupsubstituted with a C₁-C₁₀ alkyl group, a phenyl group substituted with—F, a pentalenyl group, an indenyl group, a naphthyl group, an azulenylgroup, a heptalenyl group, an indacenyl group, an acenaphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenalenyl group, a phenanthrenyl group, ananthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a naphthacenyl group, a picenyl group,a perylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a rubicenyl group, a coronenyl group, an ovalenyl group, athiophenyl group, a furanyl group, a carbazolyl group, an indolyl group,an isoindolyl group, a benzofuranyl group, a benzothiophenyl group, adibenzofuranyl group, a dibenzothiophenyl group, a benzocarbazolylgroup, a dibenzocarbazolyl group, a dibenzosilolyl group, and apyridinyl group.

The hole transport region may include at least one compound selectedfrom Compounds HT1 to HT39 below, but the exemplary embodiments are notlimited thereto:

The thickness of the hole transport region may be from about 100 Å toabout 10,000 Å, for example, about 100 Å to about 3,000 Å. When the holetransport region includes at least one selected from a hole injectionlayer and a hole transport layer, the thickness of the hole injectionlayer may be in a range of about 100 Å to about 9,000 Å, for example,about 100 Å to about 1,000 Å, and the thickness of the hole transportlayer may be in a range of about 50 Å to about 2,000 Å, for exampleabout 100 Å to about 1,500 Å. When the thicknesses of the hole transportregion, the hole injection layer, and the hole transport layer arewithin these ranges, satisfactory hole transporting characteristics maybe obtained without a substantial increase in driving voltage.

The hole transport region may further include, in addition to thesematerials, a charge-generation material for the improvement ofconductive properties. The charge-generation material may behomogeneously or non-homogeneously dispersed in the hole transportregion.

The charge-generation material may be, for example, a p-dopant.

In one exemplary embodiment, the p-dopant may have a lowest unoccupiedmolecular orbital (LUMO) energy level of about −3.5 eV or less.

The p-dopant may include at least one selected from a quinonederivative, a metal oxide, and a cyano group-containing compound, butthe exemplary embodiments are not limited thereto.

For example, the p-dopant may include at least one selected from: aquinone derivative, such as tetracyanoquinodimethane (TCNQ) or2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4-TCNQ);

a metal oxide, such as tungsten oxide or molybdenum oxide;

1,4,5,8,9,12-hexaazatriphenylene-hexacarbonitrile (HAT-CN); and

a compound represented by Formula 221 below:

but the exemplary embodiments are not limited thereto:

In Formula 221,

R₂₂₁ to R₂₂₃ may each independently be selected from a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, asubstituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted monovalentnon-aromatic condensed heteropolycyclic group, wherein at least oneselected from R₂₂₁ to R₂₂₃ may have at least one substituent selectedfrom a cyano group, —F, —Cl, —Br, —I, a C₁-C₂₀ alkyl group substitutedwith —F, a C₁-C₂₀ alkyl group substituted with —Cl, a C₁-C₂₀ alkyl groupsubstituted with —Br, and a C₁-C₂₀ alkyl group substituted with —I.

First emission layer 131 and second emission layer 132 in organic layer150.

The first emission layer 131 includes a first hole transport host, afirst electron transport host, and a first phosphorescent dopant, and,in the first emission layer 131, the amount of the first hole transporthost is greater than the amount of the first electron transport host.

In the first emission layer 131, the amount of the first hole transporthost is greater than the amount of the first electron transport host,and in the second emission layer 132, the amount of the second electrontransport host is greater than the amount of the second hole transporthost.

An emission layer 130 of the organic light-emitting device 10 includesthe first emission layer 131 and the second emission layer 132, and eachof the first emission layer 131 and the second emission layer 132includes a hole transport host and an electron transport host, each ofwhich ratio with respect to the phosphorescent dopant is controlled.Accordingly, in the emission layer 130 of the organic light-emittingdevice 10, the balance between holes and electrons is controlled, andthus, the hole-electron recombination region is maintained within theemission layer 130. Therefore, exciton-polaron quenching is prevented,and the concentration of excitons in the emission layer 130 isappropriately controlled to prevent exciton-exciton quenching. As aresult, the lifespan characteristics of the organic light-emittingdevice 10 may be significantly improved.

The first emission layer 131 and the second emission layer 132 emitlight of the same color.

According to one exemplary embodiment, each of the first emission layer13 land the second emission layer 132 may emit blue light. For example,the first emission layer 131 and the second emission layer 132 may eachemit blue light having a maximum emission wavelength of about 400 nm toabout 500 nm.

According to one exemplary embodiment, each of the first emission layer131 and the second emission layer 132 may emit green light. For example,the first emission layer 131 and the second emission layer 132 may eachemit green light having a maximum emission wavelength of about 500 nm toabout 650 nm.

According to one exemplary embodiment, each of the first emission layer131 and the second emission layer may emit red light. For example, thefirst emission layer 131 and the second emission layer 132 may each emitred light having a maximum emission wavelength of about 650 nm to about750 nm.

The amount of the first phosphorescent dopant in the first emissionlayer 131 is typically from about 0.01 parts by weight to about 50 partsby weight, for example, 0.1 parts by weight to 30 parts by weight, basedon the total weight of 100 parts by weight of the first hole transporthost and the first electron transport host, but the exemplaryembodiments are not limited thereto. The amount of the secondphosphorescent dopant in the second emission layer 132 is from about0.01 parts by weight to about 50 parts by weight, for example, 0.1 partsby weight to 30 parts by weight, based on the total weight of about 100parts by weight of the second hole transport host and the secondelectron transport host, but the exemplary embodiments are not limitedthereto.

The thickness of the first emission layer 131 and the thickness of thesecond emission layer 132 may each be about 5 nm to about 100 nm, forexample about 10 nm to about 60 nm. When the thickness of each of thefirst emission layer 131 and the second emission layer 132 is withinthese ranges, excellent light-emission characteristics may be obtainedwithout a substantial increase in driving voltage.

According to one exemplary embodiment, the first hole transport host andthe second hole transport host may each be a compound including a holetransport moiety. For example, the hole transport moiety may include acarbazole group, a dibenzofuran group, a dibenzothiophene group, anindolocarbazole group, a bis-carbazole group, or an amine group.

According to one exemplary embodiment, the first hole transport host andthe second hole transport host may each be a compound that does notinclude an electron transport moiety.

According to one exemplary embodiment, the first electron transport hostand the second electron transport host may each be a compound includingan electron transport moiety. For example, the electron transport moietymay include —CN; —F; an alkyl group substituted with —CN, or —F; an arylgroup substituted with —F, or —CN; or a C₁-C₆₀ heterocyclic groupincluding *═N—*′ moiety. For example, the electron transport moiety mayinclude a pyridine group, a pyrimidine group, a triazine group, aquinoline group, an isoquinoline group, or the like.

According to one exemplary embodiment, the first hole transport host andthe second hole transport host may each independently be a compoundrepresented by Formula 1:

According to one exemplary embodiment, the first electron transport hostand the second electron transport host may each independently be acompound represented by Formula 2:

wherein, in Formula 1 and Formula 2,

Y₁ may be selected from a single bond, —O—, —S—, —C(R₂₃)(R₂₄)—,—N(R₂₃)—, —Si(R₂₃)(R₂₄)—, —C(═O)—, —S(═O)₂—, —B(R₂₃)—, —P(R₂₃)—, and—P(═O)(R₂₃)(R₂₄)—,

k1 is 0 or 1,

CY₂₁ and CY₂₂ are each independently a C₅-C₆₀ carbocyclic group or aC₁-C₆₀ heterocyclic group,

X₃₁ may be N or C[(L₃₄)_(a34)-(R₃₁)], X₃₂ may be N orC[(L₃₅)_(a35)-(R₃₂)], X₃₃ may be N or C[(L₃₆)_(a36)-(R₃₃)],

L₂₁ to L₂₃ and L₃₁ to L₃₆ may each independently be selected from asubstituted or unsubstituted C₃-C₁₀ cycloalkylene group, a substitutedor unsubstituted C₁-C₁₀ heterocycloalkylene group, a substituted orunsubstituted C₃-C₁₀ cycloalkenylene group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted orunsubstituted C₆-C₆₀ arylene group, a substituted or unsubstitutedC₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalentnon-aromatic condensed polycyclic group, and a substituted orunsubstituted divalent non-aromatic condensed heteropolycyclic group,

a21 to a23 and a31 to a36 may each independently be an integer from 0 to5,

Ar₂₁ to Ar₂₃ and Ar₃₁ to Ar₃₃ may each independently be selected from asubstituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted orunsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀aryl group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, asubstituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted monovalentnon-aromatic condensed heteropolycyclic group,

b21 to b23 and b31 to b33 may each independently be an integer from 1 to8,

R₂₁ to R₂₄, and R₃₁ to R₃₃ may each independently be selected fromhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amidino group, a hydrazino group, a hydrazono group, asubstituted or unsubstituted C₁-C₆₀ alkyl group, a substituted orunsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstitutedC₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxygroup, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted C₁-C₆₀ heteroaryloxy group, a substituted or unsubstitutedC₁-C₆₀ heteroarylthio group, a substituted or unsubstituted monovalentnon-aromatic condensed polycyclic group, a substituted or unsubstitutedmonovalent non-aromatic condensed heteropolycyclic group,—Si(Q₁)(Q₂)(Q₃), —N(Q₁)(Q₂), —B(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)₂(Q₁), and—P(═O)(Q₁)(Q₂),

c21 and c22 may each independently be an integer from 1 to 8,

n21 and n22 may each independently be an integer from 1 to 8,

at least two selected from Ar₂₁ to Ar₂₃ and R₂₁ to R₂₂ may optionally belinked to each other to form a substituted or unsubstituted C₅-C₆₀carbocyclic group or a substituted or unsubstituted C₁-C₆₀ heterocyclicgroup,

at least two selected from Ar₃₁ to Ar₃₃ and R₃₁ to R₃₃ may optionally belinked to each other to form a substituted or unsubstituted G-C₆₀carbocyclic group or a substituted or unsubstituted C₁-C₆₀ heterocyclicgroup,

at least one substituent of the substituted C₃-C₁₀ cycloalkylene group,the substituted C₁-C₁₀ heterocycloalkylene group, the substituted C₃-C₁₀cycloalkenylene group, the substituted C₁-C₁₀ heterocycloalkenylenegroup, the substituted C₆-C₆₀ arylene group, the substituted C₁-C₆₀heteroarylene group, the substituted divalent non-aromatic fusedpolycyclic group, the substituted divalent non-aromatic fusedheteropolycyclic group, the substituted G-Go carbocyclic group, thesubstituted C₁-C₆₀ heterocyclic group, the substituted C₁-C₆₀ alkylgroup, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substitutedC₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group,the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, thesubstituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group,the substituted C₁-C₆₀ heteroaryl group, the substituted C₁-C₆₀heteroaryloxy group, the substituted G-C₆₀ heteroarylthio group, thesubstituted monovalent non-aromatic condensed polycyclic group, and thesubstituted monovalent non-aromatic condensed heteropolycyclic group isselected from:

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a G-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and aC₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group,—Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q_(U))(Q₁₂), —C(═O)(Q₁₁),—S(═O)₂(Q₁₁), and —P(═O)(Q₁₁)(Q₁₂);

a C₃-C₁₀ cycloalkyl group, a G-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —Si(Q₂₁)(Q₂₂)(Q₂₃),—N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂), —C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and—P(═O)(Q₂₁)(Q₂₂); and

—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

wherein Qi to Q₃, Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ may eachindependently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,a monovalent non-aromatic condensed heteropolycyclic group, a biphenylgroup, and a terphenyl group.

According to one exemplary embodiment, at least one selected from X₃₁ toX₃₃ in Formula 2 may be N.

According to one exemplary embodiment, the first hole transport host andthe second hole transport host may be substantially identical to eachother.

According to one exemplary embodiment, the first electron transport hostand the second electron transport host may be substantially identical toeach other.

In one or more exemplary embodiments, the first emission layer 131 andthe second emission layer 132 may each independently include a compoundrepresented by Formula 301.

[Ar₃₀₁]_(xb11)-[(L₃₀₁)_(xb1)-R₃₀₁]_(xb21)  <Formula 301>

In Formula 301,

Ar₃₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group ora substituted or unsubstituted C₁-C₆₀ heterocyclic group,

xb11 may be 1, 2, or 3,

L₃₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group,

xb1 may be an integer from 0 to 5,

R₃₀₁ may be selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group,a cyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a substituted or unsubstituted C₁-C₆₀ alkyl group, asubstituted or unsubstituted C₂-C₆₀ alkenyl group, a substituted orunsubstituted C₂-C₆₀ alkynyl group, a substituted or unsubstitutedC₁-C₆₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀ cycloalkylgroup, a substituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃), —N(Q₃₀₁)(Q₃₀₂),—B(Q₃₀₁)(Q₃₀₂), —C(═O)(Q₃₀₁), —S(═O)₂(Q₃₀₁), and —P(═O)(Q₃₀₁)(Q₃₀₂),

xb21 may be an integer from 1 to 5, and

Q₃₀₁ to Q₃₀₃ may each independently be selected from a C₁-C₁₀ alkylgroup, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, and a naphthyl group, but the exemplary embodiments arenot limited thereto.

In one exemplary embodiment, Ar₃₀₁ in Formula 301 may be selected from:

a naphthalene group, a fluorene group, a spiro-bifluorene group, abenzofluorene group, a dibenzofluorene group, a phenalene group, aphenanthrene group, an anthracene group, a fluoranthene group, atriphenylene group, a pyrene group, a chrysene group, a naphthacenegroup, a picene group, a perylene group, a pentaphene group, anindenoanthracene group, a dibenzofuran group, and a dibenzothiophenegroup; and

a naphthalene group, a fluorene group, a spiro-bifluorene group, abenzofluorene group, a dibenzofluorene group, a phenalene group, aphenanthrene group, an anthracene group, a fluoranthene group, atriphenylene group, a pyrene group, a chrysene group, a naphthacenegroup, a picene group, a perylene group, a pentaphene group, anindenoanthracene group, a dibenzofuran group, and a dibenzothiophenegroup, each substituted with at least one selected from deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, aC₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂),—C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

wherein Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, and a naphthyl group, but the exemplary embodiments arenot limited thereto.

When xb11 in Formula 301 is 2 or more, two or more Ar₃₀₁(s) may belinked to each other via a single bond.

In one or more exemplary embodiments, the compound represented byFormula 301 may be represented by Formula 301-1 or 301-2 below:

In Formulae 301-1 and 301-2,

A₃₀₁ to A₃₀₄ may each independently be selected from a benzene group, anaphthalene group, a phenanthrene group, a fluoranthene group, atriphenylene group, a pyrene group, a chrysene group, a pyridine group,a pyrimidine group, an indene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a dibenzofluorene group,an indole group, a carbazole group, a benzocarbazole group, adibenzocarbazole group, a furan group, a benzofuran group, adibenzofuran group, a naphthofuran group, a benzonaphthofuran, adinaphthofuran group, a thiophene group, a benzothiophene group, adibenzothiophene group, a naphthothiophene group, abenzonaphthothiophene group, and a dinaphthothiophene group;

X₃₀₁ may be O, S, or N-[(L₃₀₄)_(xb4)-R₃₀₄],

R₃₁₁ to R₃₁₄ may each independently be selected from hydrogen,deuterium, —F, —C₁, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₁₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),—B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

xb22 and xb23 may each independently be 0, 1, or 2,

L₃₀₁, xb1, R₃₀₁, and Q₃₁ to Q₃₃ may each be understood by referring tothe corresponding descriptions presented herein,

L₃₀₂ to L₃₀₄ may each be understood by referring to the descriptionpresented in connection with L₃₀₁,

xb2 to xb4 may each be understood by referring to the descriptionpresented in connection with xb1, and

R₃₀₂ to R₃₀₄ may each be understood by referring to the descriptionpresented in connection with R₃₀₁.

For example, L₃₀₁ to L₃₀₄ in Formulae 301, 301-1, and 301-2 may eachindependently be selected from:

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, a pyridinylene group, an imidazolylene group, apyrazolylene group, a thiazolylene group, an isothiazolylene group, anoxazolylene group, an isoxazolylene group, a thiadiazolylene group, anoxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, a triazinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a phenanthridinylenegroup, an acridinylene group, a phenanthrolinylene group, aphenazinylene group, a benzimidazolylene group, an isobenzothiazolylenegroup, a benzoxazolylene group, an isobenzoxazolylene group, atriazolylene group, a tetrazolylene group, an imidazopyridinylene group,an imidazopyrimidinylene group, and an azacarbazolylene group; and

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, a pyridinylene group, an imidazolylene group, apyrazolylene group, a thiazolylene group, an isothiazolylene group, anoxazolylene group, an isoxazolylene group, a thiadiazolylene group, anoxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, a triazinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a phenanthridinylenegroup, an acridinylene group, a phenanthrolinylene group, aphenazinylene group, a benzimidazolylene group, an isobenzothiazolylenegroup, a benzoxazolylene group, an isobenzoxazolylene group, atriazolylene group, a tetrazolylene group, an imidazopyridinylene group,an imidazopyrimidinylene group, and an azacarbazolylene group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₁₀ alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, anaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group,an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenylgroup, a hexacenyl group, a pentacenyl group, a thiophenyl group, afuranyl group, a carbazolyl group, an indolyl group, an isoindolylgroup, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranylgroup, a dibenzothiophenyl group, a benzocarbazolyl group, adibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, anoxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, a triazinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, aphenanthridinyl group, an acridinyl group, a phenanthrolinyl group, aphenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, abenzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinylgroup, an azacarbazolyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),—B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

wherein Q₃₁ to Q₃₃ are the same as described above.

In one exemplary embodiment, R₃₀₁ to R₃₀₄ in Formulae 301, 301-1, and301-2 may each independently be selected from:

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, aperylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a thiophenyl group, a furanyl group, a carbazolyl group, anindolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, an azacarbazolylgroup, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

wherein Q₃₁ to Q₃₃ are the same as described above.

In one exemplary embodiment, the emission layer 130 may include analkaline earth-metal complex as a host. For example, the host may beselected from a Be complex (for example, Compound H55), a Mg complex,and a Zn complex.

According to one exemplary embodiment, the emission layer 130 mayinclude, as a host, a compound represented by Formula 301-3.

In Formula 301-3,

A₃₀₁ to A₃₀₄ may each independently be selected from a benzene ring, anaphthalene ring, a phenanthrene ring, a fluoranthene ring, atriphenylene ring, a pyrene ring, a chrysene ring, a pyridine ring, apyrimidine ring, an indene ring, a fluorene ring, a spiro-bifluorenering, a benzofluorene ring, a dibenzofluorene ring, an indole ring, acarbazole ring, a benzocarbazole ring, a dibenzocarbazole ring, a furanring, a benzofuran ring, a dibenzofuran ring, a naphthofuran ring, abenzonaphthofuran ring, a dinaphthofuran ring, a thiophene ring, abenzothiophene ring, a dibenzothiophene ring, a naphthothiophene ring, abenzonaphthothiophene ring, and a dinaphthothiophene ring,

X₃₀₁ may be O, S, or N-[(L₃₀₄)_(X)M-R₃₀₄],

R₃₁₁ to R₃₁₄ may each independently be selected from hydrogen,deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group, —Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂),—B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

xb22 and xb23 may each independently be 0, 1, or 2,

L₃₀₁ to L₃₀₅ may each independently be selected from a substituted orunsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group,

xb1 to xb4 may each independently be an integer from 1 to 5,

xb5 may be an integer from 0 to 5,

R₃₀₁ to R₃₀₄ may each independently be selected from hydrogen,deuterium, —F, —C₁, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazine group, a hydrazone group, asubstituted or unsubstituted C₁-C₆₀ alkyl group, a substituted orunsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstitutedC₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxygroup, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, —Si(Q₃₀₁)(Q₃₀₂)(Q₃₀₃), —N(Q₃₀₁)(Q₃₀₂),—B(Q₃₀₁)(Q₃₀₂), —C(═O)(Q₃₀₁), —S(═O)₂(Q₃₀₁), and —P(═O)(Q₃₀₁)(Q₃₀₂),

wherein Q₃₁ to Q₃₃ and Q₃₀₁ to Q₃₀₃ may each independently be selectedfrom a C₁-C₁₀ alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, abiphenyl group, a terphenyl group, and a naphthyl group.

For example, the first emission layer 131 and the second emission layer132 may each independently include 9,10-di(2-naphthyl)anthracene (ADN),2-methyl-9,10-bis(naphthalen-2-yl)anthracene (MADN),9,10-di(2-naphthyl)-2-t-butyl-anthracene (TBADN),4,4′-bis(N-carbazolyl)-1,1′-biphenyl (CBP), 1,3-di-9-carbazolylbenzene(mCP), 1,3,5-tri(carbazol-9-yl)benzene (TCP), and compounds H1 to H55,as the hole transport host or the electron transport host:

First Phosphorescent Dopant and Second Phosphorescent Dopant

According to one exemplary embodiment, the first phosphorescent dopantand the second phosphorescent dopant may each be an organometalliccompound represented by Formula 401:

M(L₄₀₁)_(xc1)(L₄₀₂)_(xc2)  <Formula 401>

In Formulae 401 and 402,

M may be selected from iridium (Ir), platinum (Pt), palladium (Pd),osmium (Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu),terbium (Tb), rhodium (Rh), and thulium (Tm),

L₄₀₁ may be selected from ligands represented by Formula 402, and xc1may be 1, 2, or 3, wherein, when xc1 is 2 or more, two or more L₄₀₁(s)may be identical to or different from each other,

L₄₀₂ may be an organic ligand, and xc2 may be an integer from 0 to 4,wherein, when xc2 is 2 or more, two or more L₄₀₂(s) may be identical toor different from each other,

X₄₀₁ to X₄₀₄ may each independently be nitrogen or carbon,

X₄₀₁ and X₄₀₃ may be linked to each other via a single bond or a doublebond, and X₄₀₂ and X₄₀₄ may be linked to each other via a single bond ora double bond,

A₄₀₁ and A₄₀₂ may each independently be selected from a C₅-C₆₀carbocyclic group or a C₁-C₆₀ heterocyclic group,

X₄₀₅ may be a single bond, *—O—*′, *—S—*′, *—C(═O)—*′, *—N(Q₄₁₁)-*′,*—C(Q₄₁₁)(Q₄₁₂)-*′, *—C(Q₄₁₁)═C(Q₄₁₂)-*′, *—C(Q₄₁₁)=*′, or *═C═*′,wherein Q₄₁₁ and Q₄₁₂ may be hydrogen, deuterium, a C₁-C₂₀ alkyl group,a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, or a naphthyl group,

X₄₀₆ may be a single bond, O, or S,

R₄₀₁ and R₄₀₂ may each independently be selected from hydrogen,deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, asubstituted or unsubstituted C₁-C₂₀ alkyl group, a substituted orunsubstituted C₁-C₂₀ alkoxy group, a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroarylgroup, a substituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, a substituted or unsubstituted monovalent non-aromaticcondensed heteropolycyclic group, —Si(Q₄₀₁)(Q₄₀₂)(Q₄₀₃), —N(Q₄₀₁)(Q₄₀₂),—B(Q₄₀₁)(Q₄₀₂), —C(═O)(Q₄₀₁), —S(═O)₂(Q₄₀₁), and —P(═O)(Q₄₀₁)(Q₄₀₂), andQ₄₀₁ to Q₄₀₃ may each independently be selected from a C₁-C₁₀ alkylgroup, a C₁-C₁₀ alkoxy group, a C₆-C₂₀ aryl group, and a C₁-C₆₀heteroaryl group,

xc11 and xc12 may each independently be an integer from 0 to 10, and

* and *′ in Formula 402 each indicate a binding site to M in Formula401.

In one exemplary embodiment, A₄₀₁ and A₄₀₂ in Formula 402 may eachindependently be selected from a benzene group, a naphthalene group, afluorene group, a spiro-bifluorene group, an indene group, a pyrrolegroup, a thiophene group, a furan group, an imidazole group, a pyrazolegroup, a thiazole group, an isothiazole group, an oxazole group, anisoxazole group, a pyridine group, a pyrazine group, a pyrimidine group,a pyridazine group, a quinoline group, an isoquinoline group, abenzoquinoline group, a quinoxaline group, a quinazoline group, acarbazole group, a benzimidazole group, a benzofuran group, abenzothiophene group, an isobenzothiophene group, a benzoxazole group,an isobenzoxazole group, a triazole group, a tetrazole group, anoxadiazole group, a triazine group, a dibenzofuran group, and adibenzothiophene group.

In one or more exemplary embodiments, in Formula 402, i) X₄₀₁ may benitrogen, and X₄₀₂ may be carbon, or ii) X₄₀₁ and X₄₀₂ may each benitrogen at the same time.

In one or more exemplary embodiments, R₄₀₁ and R₄₀₂ in Formula 402 mayeach independently be selected from:

hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₂₀ alkyl group, and a C₁-C₂₀ alkoxy group;

a C₁-C₁₀ alkyl group, and a C₁-C₂₀ alkoxy group, each substituted withat least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a phenyl group, a naphthyl group, acyclopentyl group, a cyclohexyl group, an adamantanyl group, anorbomanyl group, and a norbomenyl group;

a cyclopentyl group, a cyclohexyl group, an adamantanyl group, anorbornanyl group, a norbomenyl group, a phenyl group, a biphenyl group,a terphenyl group, a naphthyl group, a fluorenyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, atriazinyl group, a quinolinyl group, an isoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a carbazolyl group, adibenzofuranyl group, and a dibenzothiophenyl group;

a cyclopentyl group, a cyclohexyl group, an adamantanyl group, anorbornanyl group, a norbomenyl group, a phenyl group, a biphenyl group,a terphenyl group, a naphthyl group, a fluorenyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, atriazinyl group, a quinolinyl group, an isoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a carbazolyl group, adibenzofuranyl group, and a dibenzothiophenyl group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₂₀ alkoxy group, acyclopentyl group, a cyclohexyl group, an adamantanyl group, anorbornanyl group, a norbomenyl group, a phenyl group, a biphenyl group,a terphenyl group, a naphthyl group, a fluorenyl group, a pyridinylgroup, a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, atriazinyl group, a quinolinyl group, an isoquinolinyl group, aquinoxalinyl group, a quinazolinyl group, a carbazolyl group, adibenzofuranyl group, and a dibenzothiophenyl group; and

—Si(Q₄₀₁)(Q₄₀₂)(Q₄₀₃), —N(Q₄₀₁)(Q₄₀₂), —B(Q₄₀₁)(Q₄₀₂), —C(═O)(Q₄₀₁),—S(═O)₂(Q₄₀₁), and —P(═O)(Q₄₀₁)(Q₄₀₂),

wherein Q₄₀₁ to Q₄₀₃ may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group,and a naphthyl group, but the exemplary embodiments are not limitedthereto.

In one or more exemplary embodiments, when xc1 in Formula 401 is 2 ormore, two A₄₀₁(S) in two or more L₄₀₁(s) may optionally be linked toeach other via X₄₀₇, which is a linking group, or two A₄₀₂(s) in two ormore L₄₀₁(s) may optionally be linked to each other via X₄₀₈, which is alinking group (see Compounds PD1 to PD4 and PD7). X₄₀₇ and X₄₀₈ may eachindependently be a single bond, *—O—*′, *—S—*′, *—C(═O)—*′,*—N(Q₄₁₃)-*′, *—C(Q₄₁₃)(Q₄₁₄)-*′, or *—C(Q₄₁₃)═C(Q₄₁₄)-*′ (wherein Q₄₁₃and Q₄₁₄ may each independently be hydrogen, deuterium, a C₁-C₂₀ alkylgroup, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, or a naphthyl group), but the exemplary embodiments arenot limited thereto.

L₄₀₂ in Formula 401 may be a monovalent, divalent, or trivalent organicligand. For example, L₄₀₂ may be selected from halogen, diketone (forexample, acetylacetonate), carboxylic acid (for example, picolinate),—C(═O), isonitrile, —CN, and phosphorus (for example, phosphine orphosphite), but the exemplary embodiments are not limited thereto.

In one or more exemplary embodiments, the first and secondphosphorescent dopants may be selected from, for example, Compounds PD1to PD26, but the exemplary embodiments are not limited thereto:

According to one exemplary embodiment, the first phosphorescent dopantand the second phosphorescent dopant may each be an organometalliccompound represented by Formula 4 or 5:

In Formulae 4 and 5,

M₄ and M₅ may each independently be selected from platinum (Pt),palladium (Pd), copper (Cu), silver (Ag), gold (Au), rhodium (Rh),iridium (Ir), ruthenium (Ru), osmium (Os), titanium (Ti), zirconium(Zr), hafnium (Hf), europium (Eu), terbium (Tb), and thulium (Tm),

n51 may be an integer from 1 to 3,

Ln₅₂ may be an organic ligand, n52 may be an integer from 0 to 2,

Y₄₁ to Y₄₄, Y₅₁ and Y₅₂ may each independently be N or C;

A₄₁ to A₄₄, A₅₁ and A₅₂ may each independently be selected from a C₅-C₆₀carbocyclic group, and a C₁-C₆₀ heterocyclic group,

at least one of A₄₁ to A₄₄ is a carbene ring, and at least one of A₅₁and A₅₂ is a carbene ring,

T₄₁ to T₄₄, T₅₁, and T₅₂ may each independently be a single bond,*—O—*′, and *—S—*′;

L₄₁ to L₄₄ and L₅₁ may each independently be selected from a singlebond, *—O—*′, *—C(R₄₅)(R₄₆)—*′, *—C(R₄₅)=*′, *═C(R₄₅)—*′,*—C(R₄₅)═C(R₄₆)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′, *—B(R₄₅)—*′,*—N(R₄₅)—*′, *—P(R₄₅)—*′, *—Si(R₄₅)(R₄₆)—*′, *—P(R₄₅)(R₄₆)—*′, and*—Ge(R₄₅)(R₄₆)—*′;

m41 to m44 and m51 may each be an integer from 0 to 3,

R₄₁ to R₄₆, R₅₁, and R₅₂ may each independently be selected fromhydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amidino group, a hydrazine group, a hydrazone group, asubstituted or unsubstituted C₁-C₆₀ alkyl group, a substituted orunsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstitutedC₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxygroup, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted monovalent non-aromatic condensed polycyclic group, asubstituted or unsubstituted monovalent non-aromatic condensedheteropolycyclic group, —Si(Q₄₁)(Q₄₂)(Q₄₃), —N(Q₄₁)(Q₄₂), —B(Q₄₁)(Q₄₂),—C(═O)(Q₄₁), —S(═O)₂(Q₄₁), and —P(═O)(Q₄₁)(Q₄₂),

regarding a pair of R₄₅ and R₄₁, a pair of R₄₅ and R₄₂, a pair of R₄₅and R₄₃, or a pair of R₄₅ and R₄₄, components of each pair may beoptionally linked to form a substituted or unsubstituted C₅-C₆₀carbocyclic group or a substituted or unsubstituted C₁-C₆₀ heterocyclicgroup,

b41 to b44, b51 and b52 may each independently be an integer from 1 to8,

* and *′ each indicate a binding site to a neighboring atom,

at least one substituent of the substituted C₅-C₆₀ carbocyclic group,the substituted C₁-C₆₀ heterocyclic group, the substituted C₁-C₆₀ alkylgroup, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substitutedC₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group,the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, thesubstituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group,the substituted G-C₆₀ heteroaryl group, the substituted monovalentnon-aromatic condensed polycyclic group, and the substituted monovalentnon-aromatic condensed heteropolycyclic group may be selected from:

deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a G-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a G-C₆₀alkoxy group;

a G-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, anda C₁-C₆₀ alkoxy group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —Si(Q₅₁)(Q₅₂)(Q₅₃),—N(Q₅₁)(Q₅₂), —B(Q₅₁)(Q₅₂), —C(═O)(Q₅₁), —S(═O)₂(Q₅₁), and—P(═O)(Q₅₁)(Q₅₂);

a C₃-C₁₀ cycloalkyl group, a G-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a monovalent non-aromatic condensed polycyclic group,and a monovalent non-aromatic condensed heteropolycyclic group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, amonovalent non-aromatic condensed polycyclic group, a monovalentnon-aromatic condensed heteropolycyclic group, —Si(Q₆₁)(Q₆₂)(Q₆₃),—N(Q₆₁)(Q₆₂), —B(Q₆₁)(Q₆₂), —C(═O)(Q₆₁), —S(═O)₂(Q₆₁), and—P(═O)(Q₆₁)(Q₆₂); and

—Si(Q₇₁)(Q₇₂)(Q₇₃), —N(Q₇₁)(Q₇₂), —B(Q₇₁)(Q₇₂), —C(═O)(Q₇₁),—S(═O)₂(Q₇₁), and —P(═O)(Q₇₁)(Q₇₂),

wherein Q₄₁ to Q₄₃, Q₅₁ to Q₅₃, Q₆₁ to Q₆₃, and Q₇₁ to Q₇₃ may eachindependently be selected from hydrogen, deuterium, —F, —Cl, —Br, —I, ahydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a G-C₆₀ alkyl group, a C₂-C₆₀alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenylgroup, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, aC₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, monovalentnon-aromatic condensed polycyclic group, monovalent non-aromaticcondensed heteropolycyclic group; a G-C₆₀ alkyl group substituted withat least one selected from deuterium, —F, and a cyano group; a C₆-C₆₀aryl group substituted with at least one selected from deuterium, —F,and a cyano group; a biphenyl group, and a terphenyl group.

At least one of A₄₁ to A₄₄ and at least one of A₅₁ and A₅₂ in Formulae 4and 5 may be a carbene ring.

For example, at least one of A₄₁ to A₄₄ and at least one of A₅₁ and A₅₂may be a group represented by one of Formulae 6-1 to 6-16:

In Formulae 6-1 to 6-16,

Z₄₁ may each independently be selected from hydrogen, deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₁-C₂₀ alkyl group, aC₂-C₂₀ alkenyl group, a C₂-C₂₀ alkynyl group, a C₁-C₂₀ alkoxy group, aphenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a phenanthrenyl group, ananthracenyl group, a triphenylenyl group, a pyridinyl group, apyrimidinyl group, a carbazolyl group, and a triazinyl group,

* and *′ each indicate a binding site to a neighboring atom.

According to one exemplary embodiment, one of A₄₁ to A₄₄ and one of A₅₁and A₅₂ in Formulae 4 and 5 may be a carbene ring.

According to one exemplary embodiment, the first phosphorescent dopantand the second phosphorescent dopant may be substantially identical toeach other.

According to one exemplary embodiment, at least one of the firstemission layer 131 and the second emission layer 132 may further includeat least one selected from a fluorescence dopant and a delayedfluorescence dopant.

According to one exemplary embodiment, the fluorescent dopant mayfurther include a compound represented by Formula 501:

In Formula 501,

Ar₅₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group ora substituted or unsubstituted C₁-C₆₀ heterocyclic group,

L₅₀₁ to L₅₀₃ may each independently be selected from a substituted orunsubstituted C₃-C₁₀ cycloalkylene group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group,

xd1 to xd3 may each independently be an integer from 0 to 3,

R₅₀₁ and R₅₀₂ may each independently be selected from a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic condensed polycyclic group, and a substituted orunsubstituted monovalent non-aromatic condensed heteropolycyclic group,and

xd4 may be an integer from 1 to 6.

In one exemplary embodiment, Ar₅₀₁ in Formula 501 may be selected from:

a naphthalene group, a heptalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a dibenzofluorene group,a phenalene group, a phenanthrene group, an anthracene group, afluoranthene group, a triphenylene group, a pyrene group, a chrysenegroup, a naphthacene group, a picene group, a perylene group, apentaphene group, an indenoanthracene group, and an indenophenanthrenegroup; and

a naphthalene group, a heptalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a dibenzofluorene group,a phenalene group, a phenanthrene group, an anthracene group, afluoranthene group, a triphenylene group, a pyrene group, a chrysenegroup, a naphthacene group, a picene group, a perylene group, apentaphene group, an indenoanthracene group, and an indenophenanthrenegroup, each substituted with at least one selected from deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₁-C₁₀ alkyl group, aC₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, a terphenylgroup, and a naphthyl group.

In one or more exemplary embodiments, L₅₀₁ to L₅₀₃ in Formula 501 mayeach independently be selected from:

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, and a pyridinylene group; and

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, and a pyridinylene group, each substituted withat least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₁₀ alkyl group, a C₁-C₂₀ alkoxy group, aphenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, and a pyridinyl group.

In one or more exemplary embodiments, R₅₀₁ and R₅₀₂ in Formula 501 mayeach independently be selected from:

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, and a pyridinyl group; and

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, and a pyridinyl group, each substituted with atleast one selected from deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a C₁-C₁₀ alkyl group, a C₁-C₂₀ alkoxy group, a phenylgroup, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, and —Si(Q₃₁)(Q₃₂)(Q₃₃),

wherein Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, and a naphthyl group.

In one or more exemplary embodiments, xd4 in Formula 501 may be 2, butthe exemplary embodiments are not limited thereto.

For example, the fluorescent dopant may be selected from Compounds FD1to FD23 below:

In one or more exemplary embodiments, the fluorescent dopant may beselected from the following compounds, but the exemplary embodiments arenot limited thereto.

According to an exemplary embodiment, the delayed fluorescence dopantmay satisfy Equation 3:

|S1(D)−T1(D)|≤0.5 eV  <Equation 3>

wherein, in Equation 3,

T1(D) is the lowest triplet excitation energy level of the dopant, and

S1(D) is the lowest singlet excitation energy level of the dopant.

The delayed fluorescence dopant satisfying Equation 3 above may emitthermally activated delayed fluorescence even at room temperature. Forexample, the delayed fluorescence dopant may satisfy the condition of|S1(D)−T1(D)|≤0.2 eV, but the exemplary embodiments are not limitedthereto.

In addition, the delayed fluorescence dopant may not include metalatoms. That is, the delayed fluorescence dopant is clearly distinguishedfrom phosphorescent dopants containing metal atoms. In one or moreexemplary embodiments, the delayed fluorescence dopant is distinguishedfrom the phosphorescent dopant in that the delayed fluorescence dopantdoes not include iridium (Ir), platinum (Pt), palladium (Pd), osmium(Os), titanium (Ti), zirconium (Zr), hafnium (Hf), europium (Eu),terbium (Tb), rhodium (Rh), and thulium (Tm).

For example, the delayed fluorescence dopant may have a D-A structureincluding an electron donor group (D) and an electron acceptor group(A). In detail, the delayed fluorescence dopant may be selected fromcompounds disclosed in Japanese Patent Application Publication No.2011-140046, Japanese Patent Application Publication No. 2013-034967,Japanese Patent Application Publication No. 2015-530745, Japanese PatentApplication Publication No. 2013-034967, Japanese Patent ApplicationPublication No. 2014-512416, Japanese Patent Application Publication No.2015-525248, Japanese Patent Application Publication No. 2013-524707,Japanese Patent Application Publication No. 2013-547225, Japanese PatentApplication Publication No. 2012-274324, Japanese Patent ApplicationPublication No. 2015-504322, the U.S. Patent Application Publication No.2012-0217869, International Publication No. WO 2015-118035,International Publication No. WO 2016-091887, International PublicationNo. WO 2016-096851, Korean Patent Application Publication No.2017-7005332, Japanese Patent Application Publication No. 2014-518737,the U.S. Patent Application Publication No. 2016-0197286, the U.S.Patent Application Publication No. 2014-0138627, the U.S. PatentApplication Publication No. 2014-0145149, the U.S. Patent ApplicationPublication No. 2014-0158992, the U.S. Patent Application PublicationNo. 2014-0145151, the U.S. Patent Application Publication No.2015-0021555, the U.S. Patent Application Publication No. 2014-0332758,Korean Patent Application Publication No. 2014-0154391, Japanese PatentApplication Publication No. 2015-148588, Japanese Patent ApplicationPublication No. 2016-506442, Japanese Patent Application Publication No.2015-531748, Japanese Patent Application Publication No. 2016-538300,Japanese Patent Application Publication No. 2016-538393, Japanese PatentApplication Publication No. 2015-095814, Japanese Patent ApplicationPublication No. 2012-538639, Japanese Patent Application Publication No.2014-525803, Japanese Patent Application Publication No. 2012-546858,Japanese Patent Application Publication No. 2016-538300, and JapanesePatent Application Publication No. 2014-538540, but the exemplaryembodiments are not limited thereto.

In one or more exemplary embodiments, the delayed fluorescence dopantmay have a structure of D-A-D or A-D-A. In one exemplary embodiment, thedelayed fluorescence dopant may be selected from the compounds disclosedin International Publication No. WO 2015-158692, Japanese PatentApplication Publication No. 2016-538435, Japanese Patent ApplicationPublication No. 2016-538426, Japanese Patent Application Publication No.2015-500308, and Japanese Patent Application Publication No.2015-527231, but the exemplary embodiments are not limited thereto.

In one exemplary embodiment, the delayed fluorescence dopant may be atransition metal complex. In one exemplary embodiment, the delayedfluorescence dopant may be a Cu complex or a Pt complex, or a compoundselected from compounds disclosed in Korean Patent ApplicationPublication No. 2012-7017497, Korean Patent Application Publication No.2013-7001396, Korean Patent Application Publication No. 2014-0068027,Korean Patent Application Publication No. 2014-7003327, and the U.S.Patent Application Publication No. 2011-0304262, etc., but the exemplaryembodiments are not limited thereto.

In one exemplary embodiment, the delayed fluorescence dopant may be acompound having a B—N structure, or a compound disclosed in the U.S.Patent Application Publication No. 2014-0027734, etc., or DABNA, but theexemplary embodiments are not limited thereto.

In one exemplary embodiment, the delayed fluorescence dopant may beselected from compounds disclosed in Japanese Patent ApplicationPublication No. 2015-508569 and Japanese Patent Application PublicationNo. 2014-554306, but the exemplary embodiments are not limited thereto.

The electron donor group (D) may be, for example, a carbazole group, adibenzofuran group, a dibenzothiophene group, an indolocarbazole group,a bis-carbazole group, or the like.

The electron acceptor group (A) may be an aryl group substituted withCN, and/or F, a π-electron deficient nitrogen-containing cyclic group,or the like.

According to one exemplary embodiment, the first emission layer 131 andthe second emission layer 132 may be in direct contact with each other.For example, other structures may not be located between the firstemission layer 131 and the second emission layer 132.

Exemplary Embodiment of FIG. 2

FIG. 2 is a schematic cross-sectional diagram of another exemplaryembodiment of an organic light-emitting device constructed according toprinciples of the invention.

Referring to FIG. 2, in the organic light-emitting device 10, theorganic layer 150 may further include a third emission layer 133 betweenthe first emission layer 131 and the second emission layer 132.

According to one exemplary embodiment, the third emission layer 133 mayinclude a third hole transport host, a third electron transport host,and a third phosphorescent dopant.

The third emission layer 133 may be understood by referring to thedescription of the first emission layer 131 and the second emissionlayer 132, as described herein.

According to one exemplary embodiment, the amount of the first holetransport host of the first emission layer 131 may be greater than theamount of the third hole transport host of the third emission layer 133,and the amount of the third hole transport host of the third emissionlayer 133 may be greater than the amount of the second hole transporthost of the second emission layer 132.

For example, the amount of hole transport host may be the greatest inthe first emission layer 131, the lowest in the second emission layer132. In addition, for example, the amount of the hole transport host maybe gradually reduced in the direction from the first emission layer 131to the second emission layer 132.

According to one exemplary embodiment, the amount of the second electrontransport host of the second emission layer 132 may be greater than theamount of the third electron transport host of the third emission layer133, and the amount of the third electron transport host of the thirdemission layer 133 may be greater than the amount of the first electrontransport host of the first emission layer 131.

For example, the amount of electron transport host may be the greatestin the second emission layer 132, the lowest in the first emission layer131. In addition, for example, the amount of the electron transport hostmay be gradually reduced in the direction from the second emission layer132 to the first emission layer 131.

Due to such a structure in the organic light-emitting device 10, becausethe balance of holes and electrons in the emission layer 130 iscontrolled, the hole-electron recombination region is maintained insidethe emission layer 130, leading to the prevention of exciton-polaronquenching, and since the concentration of excitons in the emission layer130 is appropriately controlled, exciton-exciton quenching may beprevented. As a result, the lifespan characteristics of the organiclight-emitting device 10 may be significantly improved.

According to one exemplary embodiment, the weight ratio of the thirdhole transport host and the third electron transport host of the thirdemission layer 133 may be in the range of about 4:6 to about 6:4.

According to one exemplary embodiment, at least one of the first holetransport host and the second hole transport host may be the same as thethird hole transport host. For example, the first hole transport hostmay be the same as the third hole transport host. For example, thesecond hole transport host may be the same as the third hole transporthost.

According to one exemplary embodiment, the first hole transport host,the second hole transport host, and the third hole transport host may besubstantially the same or identical.

According to one exemplary embodiment, at least one of the firstelectron transport host and the second electron transport host may bethe same as the third electron transport host. For example, the firstelectron transport host may be the same as the third electron transporthost. For example, the second electron transport host may be the same asthe third electron transport host.

According to one exemplary embodiment, the first electron transporthost, the second electron transport host, and the third electrontransport host may be substantially the same or identical.

According to one exemplary embodiment, at least one of the firstphosphorescent dopant and the second phosphorescent dopant may be thesame as the third phosphorescent dopant. For example, the firstphosphorescent dopant may be the same as the third phosphorescentdopant. For example, the second phosphorescent dopant may be the same asthe third phosphorescent dopant.

According to one exemplary embodiment, the first phosphorescent dopant,the second phosphorescent dopant, and the third phosphorescent dopantmay all be substantially the same or identical.

According to one exemplary embodiment, the first emission layer 131 andthe third emission layer 133 may be in direct contact with each other.For example, other structures may not be located between the firstemission layer 131 and the third emission layer 133.

According to one exemplary embodiment, the second emission layer 132 andthe third emission layer 133 may be in direct contact with each other.For example, other structures may not be located between the secondemission layer 132 and the third emission layer 133.

The term “electron transport moiety” used herein may include a cyanogroup, a phosphine oxide group, a sulfone oxide group, a sulfonate groupand/or a π-electron deficient nitrogen-containing cyclic group.

The term “π-electron deficient nitrogen-containing cyclic group” usedherein refers to a group including a cyclic group having at least one*—N=*′ moiety, and may be, for example, pyridine, pyrimidine, triazine,or the like.

Electron Transport Region in Organic Layer 150

The electron transport region may have i) a single-layered structureincluding a single layer including a single material, ii) asingle-layered structure including a single layer including a pluralityof different materials, or iii) a multi-layered structure having aplurality of layers including a plurality of different materials.

The electron transport region may include at least one selected from ahole blocking layer, a buffer layer, an electron control layer, anelectron transport layer, and an electron injection layer, but theexemplary embodiments are not limited thereto.

For example, the electron transport region may have an electrontransport layer/electron injection layer structure, an electron controllayer/electron transport layer/electron injection layer structure, abuffer layer/electron transport layer/electron injection layerstructure, a hole blocking layer/electron transport layer/electroninjection layer structure, a hole blocking layer/electron controllayer/electron transport layer/electron injection layer structure, or ahole blocking layer/buffer layer/electron transport layer/electroninjection layer structure, wherein, in each structure, constitutinglayers are sequentially stacked from the emission layer 130, but theexemplary embodiments are not limited thereto.

The electron transport region (for example, the hole blocking layer, thebuffer layer, the electron control layer, or the electron transportlayer in the electron transport region) may include a metal-freecompound containing at least one n electron-depleted nitrogen-containingring.

The “π electron-depleted nitrogen-containing ring” indicates a C₁-C₆₀heterocyclic group having at least one *—N=*′ moiety as a ring-formingmoiety.

For example, the “n electron-depleted nitrogen-containing ring” may bei) a 5-membered to 7-membered heteromonocyclic group having at least one*—N=*′ moiety, ii) a heteropolycyclic group in which two or more5-membered to 7-membered heteromonocyclic groups each having at leastone *—N=*′ moiety are fused with each other, or iii) a heteropolycyclicgroup in which at least one of 5-membered to 7-membered heteromonocyclicgroups, each having at least one *—N=*′ moiety, is fused with at leastone C₅-C₆₀ carbocyclic group.

Examples of the π electron-depleted nitrogen-containing ring include animidazole, a pyrazole, a thiazole, an isothiazole, an oxazole, anisoxazole, a pyridine, a pyrazine, a pyrimidine, a pyridazine, anindazole, a purine, a quinoline, an isoquinoline, a benzoquinoline, aphthalazine, a naphthyridine, a quinoxaline, a quinazoline, a cinnoline,a phenanthridine, an acridine, a phenanthroline, a phenazine, abenzimidazole, an isobenzothiazole, a benzoxazole, an isobenzoxazole, atriazole, a tetrazole, an oxadiazole, a triazine, a thiadiazole, animidazopyridine, an imidazopyrimidine, and an azacarbazole, but theexemplary embodiments are not limited thereto.

For example, the electron transport region may include a compoundrepresented by Formula 601 below:

[Ar₆₀₁]_(xe11)-[(L₆₀₁)_(xe1)-R₆₀₁]_(xe21)  <Formula 601>

In Formula 601,

Ar₆₀₁ may be a substituted or unsubstituted C₅-C₆₀ carbocyclic group ora substituted or unsubstituted C₁-C₆₀ heterocyclic group,

xe11 may be 1, 2, or 3,

L₆₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀cycloalkylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkylene group, a substituted or unsubstituted C₃-C₁₀cycloalkenylene group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenylene group, a substituted or unsubstituted C₆-C₆₀arylene group, a substituted or unsubstituted C₁-C₆₀ heteroarylenegroup, a substituted or unsubstituted divalent non-aromatic condensedpolycyclic group, and a substituted or unsubstituted divalentnon-aromatic condensed heteropolycyclic group,

xe1 may be an integer from 0 to 5,

R₆₀₁ may be selected from a substituted or unsubstituted C₃-C₁₀cycloalkyl group, a substituted or unsubstituted C₁-C₁₀ heterocycloalkylgroup, a substituted or unsubstituted C₃-C₁₀ cycloalkenyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkenyl group, asubstituted or unsubstituted C₆-C₆₀ aryl group, a substituted orunsubstituted C₆-C₆₀ aryloxy group, a substituted or unsubstitutedC₆-C₆₀ arylthio group, a substituted or unsubstituted C₁-C₆₀ heteroarylgroup, a substituted or unsubstituted monovalent non-aromatic condensedpolycyclic group, a substituted or unsubstituted monovalent non-aromaticcondensed heteropolycyclic group, —Si(Q₆₀₁)(Q₆₀₂)(Q₆₀₃), —C(═O)(Q₆₀₁),—S(═O)₂(Q₆₀₁), and —P(═O)(Q₆₀₁)(Q₆₀₂),

Q₆₀₁ to Q₆₀₃ may each independently be a C₁-C₁₀ alkyl group, a C₁-C₁₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, or anaphthyl group, and

xe21 may be an integer from 1 to 5.

In one exemplary embodiment, at least one of Ar₆₀₁(s) in the number ofxe11 and R₆₀₁(S) in the number of xe21 may include the nelectron-depleted nitrogen-containing ring.

In one exemplary embodiment, Ar₆₀₁ in Formula 601 may be selected from:

a benzene group, a naphthalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a dibenzofluorene group,a phenalene group, a phenanthrene group, an anthracene group, afluoranthene group, a triphenylene group, a pyrene group, a chrysenegroup, a naphthacene group, a picene group, a perylene group, apentaphene group, an indenoanthracene group, a dibenzofuran group, adibenzothiophene group, a carbazole group, an imidazole group, apyrazole group, a thiazole group, an isothiazole group, an oxazolegroup, an isoxazole group, a pyridine group, a pyrazine group, apyrimidine group, a pyridazine group, an indazole group, a purine group,a quinoline group, an isoquinoline group, a benzoquinoline group, aphthalazine group, a naphthyridine group, a quinoxaline group, aquinazoline group, a cinnoline group, a phenanthridine group, anacridine group, a phenanthroline group, a phenazine group, abenzimidazole group, an isobenzothiazole group, a benzoxazole group, anisobenzoxazole group, a triazole group, a tetrazole group, an oxadiazolegroup, a triazine group, a thiadiazole group, an imidazopyridine group,an imidazopyrimidine group, and an azacarbazole group; and

a benzene group, a naphthalene group, a fluorene group, aspiro-bifluorene group, a benzofluorene group, a dibenzofluorene group,a phenalene group, a phenanthrene group, an anthracene group, afluoranthene group, a triphenylene group, a pyrene group, a chrysenegroup, a naphthacene group, a picene group, a perylene group, apentaphene group, an indenoanthracene group, a dibenzofuran group, adibenzothiophene group, a carbazole group, an imidazole group, apyrazole group, a thiazole group, an isothiazole group, an oxazolegroup, an isoxazole group, a pyridine group, a pyrazine group, apyrimidine group, a pyridazine group, an indazole group, a purine group,a quinoline group, an isoquinoline group, a benzoquinoline group, aphthalazine group, a naphthyridine group, a quinoxaline group, aquinazoline group, a cinnoline group, a phenanthridine group, anacridine group, a phenanthroline group, a phenazine group, abenzimidazole group, an isobenzothiazole group, a benzoxazole group, anisobenzoxazole group, a triazole group, a tetrazole group, an oxadiazolegroup, a triazine group, a thiadiazole group, an imidazopyridine group,an imidazopyrimidine group, and an azacarbazole group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₂₀ alkyl group, a C₁-C₁₀ alkoxy group, aphenyl group, a biphenyl group, a terphenyl group, a naphthyl group,—Si(Q₃₁)(Q₃₂)(Q₃₃), —S(═O)₂(Q₃₀, and —P(═O)(Q₃₁)(Q₃₂),

wherein Q₃₁ to Q₃₃ may each independently be selected from a C₁-C₁₀alkyl group, a C₁-C₁₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, and a naphthyl group.

When xe11 in Formula 601 is 2 or more, two or more Ar₆₀₁(s) may belinked to each other via a single bond.

In one or more exemplary embodiments, Ar₆₀₁ in Formula 601 may be ananthracene group.

In one or more exemplary embodiments, a compound represented by Formula601 may be represented by Formula 601-1 below:

In Formula 601-1,

X₆₁₄ may be N or C(R₆₁₄), X₆₁₅ may be N or C(R₆₁₅), X₆₁₆ may be N orC(R₆₁₆), and at least one selected from X₆₁₄ to X₆₁₆ may be N,

L₆₁₁ to L₆₁₃ may each independently be the same as defined in connectionwith L₆₀₁,

xe611 to xe613 may each independently be the same as defined inconnection with xe1,

R₆₁₁ to R₆₁₃ may each independently be the same as defined in connectionwith R₆₀₁, and

R₆₁₄ to R₆₁₆ may each independently be selected from hydrogen,deuterium, —F, —C₁, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₁₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, and a naphthyl group.

In one exemplary embodiment, L₆₀₁ and L₆₁₁ to L₆₁₃ in Formulae 601 and601-1 may each independently be selected from:

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, a pyridinylene group, an imidazolylene group, apyrazolylene group, a thiazolylene group, an isothiazolylene group, anoxazolylene group, an isoxazolylene group, a thiadiazolylene group, anoxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, a triazinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a phenanthridinylenegroup, an acridinylene group, a phenanthrolinylene group, aphenazinylene group, a benzimidazolylene group, an isobenzothiazolylenegroup, a benzoxazolylene group, an isobenzoxazolylene group, atriazolylene group, a tetrazolylene group, an imidazopyridinylene group,an imidazopyrimidinylene group, and an azacarbazolylene group; and

a phenylene group, a naphthylene group, a fluorenylene group, aspiro-bifluorenylene group, a benzofluorenylene group, adibenzofluorenylene group, a phenanthrenylene group, an anthracenylenegroup, a fluoranthenylene group, a triphenylenylene group, a pyrenylenegroup, a chrysenylene group, a perylenylene group, a pentaphenylenegroup, a hexacenylene group, a pentacenylene group, a thiophenylenegroup, a furanylene group, a carbazolylene group, an indolylene group,an isoindolylene group, a benzofuranylene group, a benzothiophenylenegroup, a dibenzofuranylene group, a dibenzothiophenylene group, abenzocarbazolylene group, a dibenzocarbazolylene group, adibenzosilolylene group, a pyridinylene group, an imidazolylene group, apyrazolylene group, a thiazolylene group, an isothiazolylene group, anoxazolylene group, an isoxazolylene group, a thiadiazolylene group, anoxadiazolylene group, a pyrazinylene group, a pyrimidinylene group, apyridazinylene group, a triazinylene group, a quinolinylene group, anisoquinolinylene group, a benzoquinolinylene group, a phthalazinylenegroup, a naphthyridinylene group, a quinoxalinylene group, aquinazolinylene group, a cinnolinylene group, a phenanthridinylenegroup, an acridinylene group, a phenanthrolinylene group, aphenazinylene group, a benzimidazolylene group, an isobenzothiazolylenegroup, a benzoxazolylene group, an isobenzoxazolylene group, atriazolylene group, a tetrazolylene group, an imidazopyridinylene group,an imidazopyrimidinylene group, and an azacarbazolylene group, eachsubstituted with at least one selected from deuterium, —F, —Cl, —Br, —I,a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₁-C₁₀ alkyl group, a C₁-C₂₀alkoxy group, a phenyl group, a biphenyl group, a terphenyl group, anaphthyl group, a fluorenyl group, a spiro-bifluorenyl group, abenzofluorenyl group, a dibenzofluorenyl group, a phenanthrenyl group,an anthracenyl group, a fluoranthenyl group, a triphenylenyl group, apyrenyl group, a chrysenyl group, a perylenyl group, a pentaphenylgroup, a hexacenyl group, a pentacenyl group, a thiophenyl group, afuranyl group, a carbazolyl group, an indolyl group, an isoindolylgroup, a benzofuranyl group, a benzothiophenyl group, a dibenzofuranylgroup, a dibenzothiophenyl group, a benzocarbazolyl group, adibenzocarbazolyl group, a dibenzosilolyl group, a pyridinyl group, animidazolyl group, a pyrazolyl group, a thiazolyl group, an isothiazolylgroup, an oxazolyl group, an isoxazolyl group, a thiadiazolyl group, anoxadiazolyl group, a pyrazinyl group, a pyrimidinyl group, a pyridazinylgroup, a triazinyl group, a quinolinyl group, an isoquinolinyl group, abenzoquinolinyl group, a phthalazinyl group, a naphthyridinyl group, aquinoxalinyl group, a quinazolinyl group, a cinnolinyl group, aphenanthridinyl group, an acridinyl group, a phenanthrolinyl group, aphenazinyl group, a benzimidazolyl group, an isobenzothiazolyl group, abenzoxazolyl group, an isobenzoxazolyl group, a triazolyl group, atetrazolyl group, an imidazopyridinyl group, an imidazopyrimidinylgroup, and an azacarbazolyl group,

but the exemplary embodiments are not limited thereto.

In one or more exemplary embodiments, xe1 and xe611 to xe613 in Formulae601 and 601-1 may each independently be 0, 1, or 2.

In one or more exemplary embodiments, R₆₀₁ and R₆₁₁ to R₆₁₃ in Formula601 and 601-1 may each independently be selected from:

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group;

a phenyl group, a biphenyl group, a terphenyl group, a naphthyl group, afluorenyl group, a spiro-bifluorenyl group, a benzofluorenyl group, adibenzofluorenyl group, a phenanthrenyl group, an anthracenyl group, afluoranthenyl group, a triphenylenyl group, a pyrenyl group, a chrysenylgroup, a perylenyl group, a pentaphenyl group, a hexacenyl group, apentacenyl group, a thiophenyl group, a furanyl group, a carbazolylgroup, an indolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group, each substituted with at least one selected fromdeuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₂₀alkyl group, a C₁-C₂₀ alkoxy group, a phenyl group, a biphenyl group, aterphenyl group, a naphthyl group, a fluorenyl group, aspiro-bifluorenyl group, a benzofluorenyl group, a dibenzofluorenylgroup, a phenanthrenyl group, an anthracenyl group, a fluoranthenylgroup, a triphenylenyl group, a pyrenyl group, a chrysenyl group, aperylenyl group, a pentaphenyl group, a hexacenyl group, a pentacenylgroup, a thiophenyl group, a furanyl group, a carbazolyl group, anindolyl group, an isoindolyl group, a benzofuranyl group, abenzothiophenyl group, a dibenzofuranyl group, a dibenzothiophenylgroup, a benzocarbazolyl group, a dibenzocarbazolyl group, adibenzosilolyl group, a pyridinyl group, an imidazolyl group, apyrazolyl group, a thiazolyl group, an isothiazolyl group, an oxazolylgroup, an isoxazolyl group, a thiadiazolyl group, an oxadiazolyl group,a pyrazinyl group, a pyrimidinyl group, a pyridazinyl group, a triazinylgroup, a quinolinyl group, an isoquinolinyl group, a benzoquinolinylgroup, a phthalazinyl group, a naphthyridinyl group, a quinoxalinylgroup, a quinazolinyl group, a cinnolinyl group, a phenanthridinylgroup, an acridinyl group, a phenanthrolinyl group, a phenazinyl group,a benzimidazolyl group, an isobenzothiazolyl group, a benzoxazolylgroup, an isobenzoxazolyl group, a triazolyl group, a tetrazolyl group,an imidazopyridinyl group, an imidazopyrimidinyl group, and anazacarbazolyl group; and

—S(═O)₂(Q₆₀₁) and —P(═O)(Q₆₀₁)(Q₆₀₂),

wherein Q₆₀₁ and Q₆₀₂ are the same as described above.

The electron transport region may include at least one compound selectedfrom Compounds ET1 to ET36 below, but the exemplary embodiments are notlimited thereto:

In one or more exemplary embodiments, the electron transport region mayinclude at least one compound selected from2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP),4,7-diphenyl-1,10-phenanthroline (Bphen),tris-(8-hydroxyquinoline)aluminum (Alq₃),bis(8-hydroxy-2-methylquinoline)-(4-phenylphenoxy)aluminum (BAlq),3-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-4-phenyl-4H-1,2,4-triazole(TAZ), and 4-(naphthalen-1-yl)-3,5-diphenyl-1,2,4-triazole (NTAZ),TSPO1, TPBI, DPEPO below:

The thickness of the hole blocking layer, the buffer layer, or theelectron control layer may be in a range of about 20 Å to about 1,000 Å,for example, about 30 Å to about 300 Å. When the thicknesses of the holeblocking layer, the buffer layer, and the electron control layer arewithin these ranges, the electron transport region may have excellenthole blocking characteristics or electron control characteristicswithout a substantial increase in driving voltage.

According to one exemplary embodiment, the electron transport regionincludes the hole blocking layer, the hole blocking layer is in directcontact with the second emission layer, and the hole blocking materialcontained in the hole blocking layer is substantially the same oridentical as the second electron transport host, and optionally, issubstantially identical as the hole transport host.

The thickness of the electron transport layer may be from about 100 Å toabout 1,000 Å, for example, about 150 Å to about 500 Å. When thethickness of the electron transport layer is within the range describedabove, the electron transport layer may have satisfactory electrontransport characteristics without a substantial increase in drivingvoltage.

The electron transport region (for example, the electron transport layerin the electron transport region) may further include, in addition tothe materials described above, a metal-containing material.

The metal-containing material may include at least one selected fromalkali metal complex and alkaline earth-metal complex. The alkali metalcomplex may include a metal ion selected from a Li ion, a Na ion, a Kion, a Rb ion, and a Cs ion, and the alkaline earth-metal complex mayinclude a metal ion selected from a Be ion, a Mg ion, a Ca ion, a Srion, and a Ba ion. A ligand coordinated with the metal ion of the alkalimetal complex or the alkaline earth-metal complex may be selected from ahydroxy quinoline, a hydroxy isoquinoline, a hydroxy benzoquinoline, ahydroxy acridine, a hydroxy phenanthridine, a hydroxy phenyloxazole, ahydroxy phenylthiazole, a hydroxy diphenyloxadiazole, a hydroxydiphenylthiadiazole, a hydroxy phenylpyridine, a hydroxyphenylbenzimidazole, a hydroxy phenylbenzothiazole, a bipyridine, aphenanthroline, and a cyclopentadiene, but the exemplary embodiments arenot limited thereto.

For example, the metal-containing material may include a Li complex. TheLi complex may include, for example, Compound ET-D1 (lithium quinolate,LiQ) or ET-D2 below:

The electron transport region may include an electron injection layerthat facilitates electron injection from the second electrode 190. Theelectron injection layer may directly contact the second electrode 190.

The electron injection layer may have i) a single-layered structureincluding a single layer including a single material, ii) asingle-layered structure including a single layer including a pluralityof different materials, or iii) a multi-layered structure having aplurality of layers including a plurality of different materials.

The electron injection layer may include an alkali metal, an alkalineearth metal, a rare earth metal, an alkali metal compound, an alkalineearth-metal compound, a rare earth metal compound, an alkali metalcomplex, an alkaline earth-metal complex, a rare earth metal complex, orany combination thereof.

The alkali metal may be selected from Li, Na, K, Rb, and Cs. In oneexemplary embodiment, the alkali metal may be Li, Na, or Cs. In one ormore exemplary embodiments, the alkali metal may be Li or Cs, but theexemplary embodiments are not limited thereto.

The alkaline earth metal may be selected from Mg, Ca, Sr, and Ba.

The rare earth metal may be selected from Sc, Y, Ce, Tb, Yb, and Gd.

The alkali metal compound, the alkaline earth-metal compound, and therare earth metal compound may be selected from oxides and halides (forexample, fluorides, chlorides, bromides, or iodides) of the alkalimetal, the alkaline earth-metal, and the rare earth metal.

The alkali metal compound may be selected from alkali metal oxides, suchas Li₂O, Cs₂O, or K₂O, and alkali metal halides, such as LiF, NaF, CsF,KF, LiI, NaI, CsI, KI, or RbF In one exemplary embodiment, the alkalimetal compound may be selected from LiF, Li₂O, NaF, LiI, NaI, CsI, andKI, but the exemplary embodiments are not limited thereto.

The alkaline earth-metal compound may be selected from alkalineearth-metal oxides, such as BaO, SrO, CaO, Ba_(x)SR_(1-x)O (0<x<1), orBa_(x)Ca_(1-x)O (0<x<l). In one exemplary embodiment, the alkalineearth-metal compound may be selected from BaO, SrO, and CaO, but theexemplary embodiments are not limited thereto.

The rare earth metal compound may be selected from YbF₃, ScF₃, Sc₂O₃,Y₂O₃, Ce₂O₃, GdF₃ and TbF₃. In one exemplary embodiment, the rare earthmetal compound may be selected from YbF₃, ScF₃, TbF₃, YbI₃, ScI₃, andTbI₃, but the exemplary embodiments are not limited thereto.

The alkali metal complex, the alkaline earth-metal complex, and the rareearth metal complex may include an ion of alkali metal, alkalineearth-metal, and rare earth metal as described above, and a ligandcoordinated with a metal ion of the alkali metal complex, the alkalineearth-metal complex, or the rare earth metal complex may be selectedfrom hydroxy quinoline, hydroxy isoquinoline, hydroxy benzoquinoline,hydroxy acridine, hydroxy phenanthridine, hydroxy phenyloxazole, hydroxyphenylthiazole, hydroxy diphenyloxadiazole, hydroxy diphenylthiadiazole,hydroxy phenylpyridine, hydroxy phenylbenzimidazole, hydroxyphenylbenzothiazole, bipyridine, phenanthroline, and cyclopentadiene,but the exemplary embodiments are not limited thereto.

The electron injection layer may consist of (or include) an alkalimetal, an alkaline earth metal, a rare earth metal, an alkali metalcompound, an alkaline earth-metal compound, a rare earth metal compound,an alkali metal complex, an alkaline earth-metal complex, a rare earthmetal complex, or any combination thereof, as described above. In one ormore exemplary embodiments, the electron injection layer may furtherinclude an organic material. When the electron injection layer furtherincludes an organic material, an alkali metal, an alkaline earth metal,a rare earth metal, an alkali metal compound, an alkaline earth-metalcompound, a rare earth metal compound, an alkali metal complex, analkaline earth-metal complex, a rare earth metal complex, or anycombinations thereof may be homogeneously or non-homogeneously dispersedin a matrix including the organic material.

The thickness of the electron injection layer may be in a range of about1 Å to about 100 Å, for example, about 3 Å to about 90 Å. When thethickness of the electron injection layer is within these ranges,satisfactory electron injection characteristics may be obtained withoutsubstantial increase in driving voltage.

The second electrode 190 may be located on the organic layer 150 havingsuch a structure. A material for forming the second electrode 190 may bemetal, an alloy, an electrically conductive compound, or a combinationthereof, which have a low work function.

The second electrode 190 may include at least one selected from lithium(Li), silver (Ag), magnesium (Mg), aluminum (Al), aluminum-lithium(Al—Li), calcium (Ca), magnesium-indium (Mg—In), magnesium-silver(Mg—Ag), an ITO, and an IZO, but the exemplary embodiments are notlimited thereto. The second electrode 190 may be a transmissiveelectrode, a semi-transmissive electrode, or a reflective electrode.

The second electrode 190 may have a single-layered structure, or amulti-layered structure including two or more layers.

A substrate may be additionally located under the first electrode 110 (asurface of the first electrode 110 which does not contact the organiclayer) or above the second electrode 190 (a surface of the secondelectrode 190 which does not contact the organic layer). The substratemay be a glass substrate or a plastic substrate, each having excellentmechanical strength, thermal stability, transparency, surfacesmoothness, ease of handling, and water resistance.

Exemplary Embodiment of FIG. 3

FIG. 3 is a schematic cross-sectional diagram of yet another exemplaryembodiment of an organic light-emitting device constructed according toprinciples of the invention.

Referring to FIG. 3, the organic light-emitting device 20 includes: afirst electrode 210; a second electrode 290 facing the first electrode210; and an organic layer 250 including an emission layer 230 andlocated between the first electrode 210 and the second electrode 290,and

The emission layer 230 includes a first emission area 231 and a secondemission area 232, wherein the first emission area 231 of the emissionlayer 230 is closer to the first electrode 210 than the second emissionarea 232.

Each of the first emission area 231 and the second emission area 232includes a hole transport host, an electron transport host, and aphosphorescent dopant.

The amount of the hole transport host in the first emission area 231 isgreater than the amount of the electron transport host in the secondemission area 232, the amount of the electron transport host in thesecond emission area 232 is greater than the amount of the holetransport host in the first emission area 231, and the phosphorescentdopant is an organometallic compound represented by Formula 4 or 5:

Formulae 4 and 5 are the same as described above.

The organic light-emitting device 20 has an emission layer 230 includingthe first emission area 231 and the second emission area 232, and theamount of the hole transport host and the amount of the electrontransport host are controlled in each of the first emission area 231 andthe second emission area 232, and the phosphorescent dopant necessarilyincludes a carbene ring in a ligand thereof. Accordingly, in the organiclight-emitting device 20, because the balance of holes and electrons inthe emission layer 230 is controlled, the hole-electron recombinationregion is maintained inside the emission layer 230, leading to theprevention of exciton-polar on quenching, and since the concentration ofexcitons in the emission layer 230 is appropriately controlled,exciton-exciton quenching may be prevented. As a result, the lifespancharacteristics of the organic light-emitting device 20 may besignificantly improved.

According to one exemplary embodiment, the amount of a hole transporthost in an emission layer 230 may be gradually decreased from the firstemission area 231 to the second emission area 232, and the amount of anelectron transport host in the emission layer 230 may be graduallyincreased from the first emission area 231 to the second emission area232.

The hole transport host may be understood by referring to thedescription of the first hole transport host and the second holetransport host above, and the electron transport host may independentlybe substantially the same or identical as defined above as the firstelectron transport host and the second electron transport host. Inaddition, the phosphorescent dopant may independently be substantiallythe same or identical as defined above as the first phosphorescentdopant and the second phosphorescent dopant.

According to one exemplary embodiment, the emission layer 230 may emitblue light having the maximum emission wavelength of about 400 nm toabout 500 nm.

Other elements of the organic light-emitting device 20 may be,independently, as corresponding elements as the organic light-emittingdevice 10, as described above.

One exemplary embodiment provides an organic light-emitting deviceincluding: a first electrode; a second electrode facing the firstelectrode; m emission units between the first electrode and the secondelectrode; and m−1 charge generating unit(s) between adjacent emissionunits, wherein m is two or more natural numbers, and

each of the emission units includes at least one emission layer 230.

According to one exemplary embodiment, at least one of the emissionunits may include a first emission layer 131 and a second emission layer132 as described above, or a first emission layer 131, a second emissionlayer 132, and a third emission layer 133 as described above.

According to one exemplary embodiment, at least one of the emissionunits may include an emission layer 230 including the first emissionarea 231 and the second emission area 232 as described above. Accordingto one exemplary embodiment, the maximum emission wavelength emittedfrom at least one emission unit of the m emission units may be identicalto the maximum emission wavelength of light emitted from at least oneemission unit of the remaining emission units.

According to one exemplary embodiment, the maximum emission wavelengthemitted from at least one emission unit of the m emission units may bedifferent from the maximum emission wavelength of light emitted from atleast one emission unit of the remaining emission units.

In one exemplary embodiment, m may be 2,the m emission units may includea first emission unit and a second emission unit,

the first emission unit and the second emission unit may be understoodby referring to the description of the emission unit, as describedabove,

m−1 charge generating layers may include a first charge generatinglayer,

the first charge generating layer is located between the first emissionunit and the second emission unit,

the first emission unit is located between the first electrode and thefirst charge generating layer,

the second emission unit is located between the first charge generatinglayer and a second charge generating layer,

the first charge generating layer includes a 1n-type charge generatinglayer and a 1p-type charge generating layer, wherein the 1n-type chargegenerating layer is located between the first emission unit and thesecond emission unit, and the 1p-type charge generating layer is locatedbetween the 1n-type charge generating layer and the second emissionunit,

the first emission unit emits first-color light, the second emissionunit emits second-color light, the maximum emission wavelength of thefirst-color light and the maximum emission wavelength of thesecond-color light may be identical to or different from each other, and

mixed color-light in which the first-color light and the second-colorlight are mixed with each other may be emitted.

In one exemplary embodiment, m may be 3,

the m emission units may include a first emission unit, a secondemission unit, and a third emission unit,

the first emission unit, the second emission unit, and the thirdemission unit may be understood by referring to the description of theemission unit as described herein,

m−1 charge generating layers may include a first charge generating layerand a second charge generating layer,

the first charge generating layer is located between the first emissionunit and the second emission unit,

the second charge generating layer is located between the secondemission unit and the third emission unit,

the first emission unit may be located between the first electrode andthe first charge generating layer,

the second emission unit may be located between the first chargegenerating layer and the second charge generating layer,

the third emission unit may be located between the second chargegenerating layer and the second electrode,

the first charge generating layer may include a 1n-type chargegenerating layer and a 1p-type charge generating layer, wherein the1n-type charge generating layer is located between the first emissionunit and the second emission unit, and the 1p-type charge generatinglayer is located between the 1n-type charge generating layer and thesecond emission unit,

the second charge generating layer may include an 2n-type chargegenerating layer and an 2p-type charge generating layer, wherein the2n-type charge generating layer is located between the second emissionunit and the third emission unit, and the 2p-type charge generatinglayer is located between the 2n-type charge generating layer and thethird emission unit,

the first emission unit emits a first-color light, the second emissionunit emits a second-color light, the third emission unit emits a thirdcolor light,

the maximum emission wavelength of the first color light, the maximumemission wavelength of the second color light, and the maximum emissionwavelength of the third color light may be identical to or differentfrom each other, and

mixed color-light in which the first-color light, the second-colorlight, and the third-color light are mixed with each other may beemitted.

The organic light-emitting device 10 or 20 may further include a cappinglayer positioned in a direction in which light is emitted. The cappinglayer may increase external luminescence efficiency according to theprinciple of constructive interference.

The capping layer may be an organic capping layer consisting of anorganic material, an inorganic capping layer consisting of an inorganicmaterial, or a composite capping layer including an organic material andan inorganic material.

The capping layer may include at least one material selected fromcarbocyclic compounds, heterocyclic compounds, amine-based compounds,porphyrine derivatives, phthalocyanine derivatives, a naphthalocyaninederivatives, alkali metal complexes, and alkaline earth metal complexes.The carbocyclic compound, the heterocyclic compound, and the amine-basedcompound may be optionally substituted with a substituent containing atleast one element selected from O, N, S, Se, Si, F, Cl, Br, and I. Inone exemplary embodiment, the capping layer may include an amine-basedcompound.

In one or more exemplary embodiments, the capping layer may include acompound represented by Formula 201 or a compound represented by Formula202.

In one or more exemplary embodiments, the capping layer may include acompound selected from Compounds HT28 to HT33 and Compounds CP1 to CP5below, but the exemplary embodiments are not limited thereto.

Hereinbefore, the organic light-emitting device 10 or 20 has beendescribed in connection with FIGS. 1 to 3, but the exemplary embodimentsare not limited thereto.

Layers constituting the hole transport region, an emission layer 130 or230, and layers constituting the electron transport region may be formedin a certain region by using one or more suitable methods selected fromvacuum deposition, spin coating, casting, Langmuir-Blodgett (LB)deposition, ink-jet printing, laser-printing, and laser-induced thermalimaging (LITI).

When layers constituting the hole transport region, an emission layer130 or 230, and layers constituting the electron transport region areformed by vacuum deposition, the deposition may be performed at adeposition temperature of about 100° C. to about 500° C., a vacuumdegree of about 10′⁸ torr to about 10′³ torr, and a deposition speed ofabout 0.01 Å/sec to about 100 Å/sec by taking into account a material tobe included in a layer to be formed, and the structure of a layer to beformed.

When layers constituting the hole transport region, an emission layer130 or 230, and layers constituting the electron transport region areformed by spin coating, the spin coating may be performed at a coatingspeed of about 2,000 rpm to about 5,000 rpm and at a heat treatmenttemperature of about 80° C. to 200° C. by taking into account a materialto be included in a layer to be formed, and the structure of a layer tobe formed.

FIG. 4 is a schematic diagram of an exemplary embodiment of an apparatuscontaining an organic light-emitting device constructed according toprinciples of the invention.

The organic light-emitting device 10 or 20 may be included in variousapparatuses.

Another aspect of the invention provides an apparatus 300 including theorganic light-emitting device 10. Although the organic light-emittingdevice 10 is depicted in FIG. 4, the organic light-emitting device 20may be used instead of or in addition to the organic light-emittingdevice 10.

The apparatus 300 may further include, in addition to the organiclight-emitting device 10, a thin film transistor 310. Here, the thinfilm transistor 310 may include a source electrode 320, an activationlayer 330, and a drain electrode 340, wherein the first electrode 90 ofthe organic light-emitting device 10 may be in electrical connectionwith one or both of the source electrode 320 and the drain electrode 340of the thin-film transistor 310.

For example, the apparatus 300 may be a light-emitting apparatus, anauthentication apparatus, or an electronic apparatus, but the exemplaryembodiments are not limited thereto.

The light-emitting apparatus 300 may be used as various displays, lightsources, and the like.

The authentication apparatus 300 may be, for example, a biometricauthentication apparatus for authenticating an individual by usingbiometric information of a biometric body (for example, a finger tip, apupil, or the like).

The authentication apparatus may further include, in addition to theorganic light-emitting device, a biometric information collector.

The electronic apparatus may be applied to personal computers (forexample, a mobile personal computer), mobile phones, digital cameras,electronic organizers, electronic dictionaries, electronic gamemachines, medical instruments (for example, electronic thermometers,sphygmomanometers, blood glucose meters, pulse measurement devices,pulse wave measurement devices, electrocardiogram (ECG) displays,ultrasonic diagnostic devices, or endoscope displays), fish finders,various measuring instruments, meters (for example, meters for avehicle, an aircraft, and a vessel), projectors, and the like, but theexemplary embodiments are not limited thereto.

The term “C₁-C₆₀ alkyl group” as used herein refers to a linear orbranched aliphatic saturated hydrocarbon monovalent group having 1 to 60carbon atoms, and examples thereof include a methyl group, an ethylgroup, a propyl group, an isobutyl group, a sec-butyl group, atert-butyl group, a pentyl group, an isoamyl group, and a hexyl group.The term “C₁-C₆₀ alkylene group” as used herein refers to a divalentgroup having a structure corresponding to the C₁-C₆₀ alkyl group.

The term “C₂-C₆₀ alkenyl group” as used herein refers to a hydrocarbongroup having at least one carbon-carbon double bond in the middle or atthe terminus of the C₂-C₆₀ alkyl group, and examples thereof include anethenyl group, a propenyl group, and a butenyl group. The term “C₂-C₆₀alkenylene group” as used herein refers to a divalent group having astructure corresponding to the C₂-C₆₀ alkenyl group.

The term “C₂-C₆₀ alkynyl group” as used herein refers to a hydrocarbongroup having at least one carbon-carbon triple bond in the middle or atthe terminus of the C₂-C₆₀ alkyl group, and examples thereof include anethynyl group, and a propynyl group. The term “C₂-C₆₀ alkynylene group”as used herein refers to a divalent group having a structurecorresponding to the C₂-C₆₀ alkynyl group.

The term “C₁-C₆₀ alkoxy group” as used herein refers to a monovalentgroup represented by—OA₁₀₁ (wherein A₁₀₁ is the C₁-C₆₀ alkyl group), andexamples thereof include a methoxy group, an ethoxy group, and anisopropyloxy group.

The term “C₃-C₁₀ cycloalkyl group” as used herein refers to a monovalentsaturated hydrocarbon monocyclic group having 3 to 10 carbon atoms, andexamples thereof include a cyclopropyl group, a cyclobutyl group, acyclopentyl group, a cyclohexyl group, and a cycloheptyl group. The term“C₃-C₁₀ cycloalkylene group” as used herein refers to a divalent grouphaving a structure corresponding to the C₃-C₁₀ cycloalkyl group.

The term “C₁-C₁₀ heterocycloalkyl group” as used herein refers to amonovalent monocyclic group having at least one heteroatom selected fromN, O, Si, P, and S as a ring-forming atom and 1 to 10 carbon atoms, andexamples thereof include a 1,2,3,4-oxatriazolidinyl group, atetrahydrofuranyl group, and a tetrahydrothiophenyl group. The term“C₁-C₁₀ heterocycloalkylene group” as used herein refers to a divalentgroup having a structure corresponding to the C₁-C₁₀ heterocycloalkylgroup.

The term “C₃-C₁₀ cycloalkenyl group” as used herein refers to amonovalent monocyclic group that has 3 to 10 carbon atoms and at leastone carbon-carbon double bond in the ring thereof and no aromaticity,and examples thereof include a cyclopentenyl group, a cyclohexenylgroup, and a cycloheptenyl group. The term “C₃-C₁₀ cycloalkenylenegroup” as used herein refers to a divalent group having a structurecorresponding to the C₃-C₁₀ cycloalkenyl group.

The term “C₁-C₁₀ heterocycloalkenyl group” as used herein refers to amonovalent monocyclic group that has at least one heteroatom selectedfrom N, O, Si, P, and S as a ring-forming atom, 1 to 10 carbon atoms,and at least one carbon-carbon double bond in its ring. Non-limitingexamples of the C₁-C₁₀ heterocycloalkenyl group include a4,5-dihydro-1,2,3,4-oxatriazolyl group, a 2,3-dihydrofuranyl group, anda 2,3-dihydrothiophenyl group. The term “C₁-C₁₀ heterocycloalkenylenegroup” as used herein refers to a divalent group having a structurecorresponding to the C₁-C₁₀ heterocycloalkenyl group.

The term “C₆-C₆₀ aryl group” as used herein refers to a monovalent grouphaving a carbocyclic aromatic system having 6 to 60 carbon atoms, and aC₆-C₆₀ arylene group used herein refers to a divalent group having acarbocyclic aromatic system having 6 to 60 carbon atoms. Non-limitingexamples of the C₆-C₆₀ aryl group include a phenyl group, a naphthylgroup, an anthracenyl group, a phenanthrenyl group, a pyrenyl group, anda chrysenyl group. When the C₆-C₆₀ aryl group and the C₆-C₆₀ arylenegroup each include two or more rings, the rings may be fused to eachother.

The term “C₁-C₆₀ heteroaryl group” as used herein refers to a monovalentgroup having a carbocyclic aromatic system that has at least oneheteroatom selected from N, O, Si, P, and S as a ring-forming atom, inaddition to 1 to 60 carbon atoms. The term “C₁-C₆₀ heteroarylene group”as used herein refers to a divalent group having a carbocyclic aromaticsystem that has at least one heteroatom selected from N, O, Si, P, and Sas a ring-forming atom, in addition to 1 to 60 carbon atoms.Non-limiting examples of the C₁-C₆₀ heteroaryl group include a pyridinylgroup, a pyrimidinyl group, a pyrazinyl group, a pyridazinyl group, atriazinyl group, a quinolinyl group, and an isoquinolinyl group. Whenthe C₁-C₆₀ heteroaryl group and the C₁-C₆₀ heteroarylene group eachinclude two or more rings, the rings may be fused with each other.

The term “C₆-C₆₀ aryloxy group” as used herein refers to—OA₁₀₂ (whereinA₁₀₂ is the C₆-C₆₀ aryl group), and the term “C₆-C₆₀ arylthio group” asused herein refers to—SA₁₀₃ (wherein A₁₀₃ is the C₆-C₆₀ aryl group).

The term “C₁-C₆₀ heteroaryloxy group” as used herein refers to—OA₁₀₄(wherein A₁₀₄ is the C₁-C₆₀ heteroaryl group), and a C₁-C₆₀heterorylthio group used herein refers to—SA₁₀₅ (wherein A₁₀₅ is theC₁-C₆₀ heteroaryl group).

The term “monovalent non-aromatic fused polycyclic group” as used hereinrefers to a monovalent group (for example, having 8 to 60 carbon atoms)having two or more rings fused with each other, only carbon atoms asring-forming atoms, and no aromaticity in its entire molecularstructure. A detailed example of the monovalent non-aromatic fusedpolycyclic group is a fluorenyl group. The term “divalent non-aromaticfused polycyclic group” as used herein refers to a divalent group havinga structure corresponding to the monovalent non-aromatic fusedpolycyclic group.

The term “monovalent non-aromatic fused heteropolycyclic group” as usedherein refers to a monovalent group (for example, having 1 to 60 carbonatoms) having two or more rings fused to each other, at least oneheteroatom selected from N, O, Si, P, and S, other than carbon atoms, asa ring-forming atom, and no aromaticity in its entire molecularstructure. An example of the monovalent non-aromatic fusedheteropolycyclic group is a carbazolyl group. The term “divalentnon-aromatic fused heteropolycyclic group” as used herein refers to adivalent group having a structure corresponding to the monovalentnon-aromatic fused heteropolycyclic group.

The term “C₅-C₆₀ carbocyclic group” as used herein refers to amonocyclic or polycyclic group having 5 to 60 carbon atoms in which aring-forming atom is a carbon atom only. The term “C₅-C₆₀ carbocyclicgroup” as used herein refers to an aromatic carbocyclic group or anon-aromatic carbocyclic group. The C₅-C₆₀ carbocyclic group may be aring, such as benzene, a monovalent group, such as a phenyl group, or adivalent group, such as a phenylene group. In one or more exemplaryembodiments, depending on the number of substituents connected to theC₅-C₆₀ carbocyclic group, the C₅-C₆₀ carbocyclic group may be atrivalent group or a quadrivalent group.

The term “C₁-C₆₀ heterocyclic group” as used herein refers to a grouphaving a structure corresponding to the C₅-C₆₀ carbocyclic group, exceptthat as a ring-forming atom, at least one heteroatom selected from N, O,Si, P, and S is used in addition to carbon (the number of carbon atomsmay be in a range of 1 to 60).

The terms “hydrogen” and “deuterium” refer to their respective atoms andcorresponding radicals, and the terms “—F, —Cl, —Br, and —I” areradicals of, respectively, fluorine, chlorine, bromine, and iodine.

In the exemplary embodiments, at least one substituent of thesubstituted C₅-C₆₀ carbocyclic group, the substituted C₁-C₆₀heterocyclic group, the substituted C₁-C₂₀ alkylene group, thesubstituted C₂-C₂₀ alkenylene group, the substituted C₃-C₁₀cycloalkylene group, the substituted C₁-C₁₀ heterocycloalkylene group,the substituted C₃-C₁₀ cycloalkenylene group, the substituted C₁-C₁₀heterocycloalkenylene group, the substituted C₆-C₆₀ arylene group, thesubstituted C₁-C₆₀ heteroarylene group, the substituted divalentnon-aromatic fused polycyclic group, the substituted divalentnon-aromatic fused heteropolycyclic group, the substituted C₁-C₆₀ alkylgroup, the substituted C₂-C₆₀ alkenyl group, the substituted C₁-C₆₀alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substitutedC₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group,the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, thesubstituted C₆-C₆₀ aryloxy group, the substituted C₆-C₆₀ arylthio group,the substituted C₁-C₆₀ heteroaryl group, the substituted C₁-C₆₀heteroaryloxy group, the substituted C₁-C₆₀ heteroarylthio group, thesubstituted monovalent non-aromatic fused polycyclic group, and thesubstituted monovalent non-aromatic fused heteropoly cyclic group may beselected from:

deuterium (-D), —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, anda C₁-C₆₀ alkoxy group;

a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group,and a C₁-C₆₀ alkoxy group, each substituted with at least one selectedfrom deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, anitro group, an amidino group, a hydrazino group, a hydrazono group, aC₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthiogroup, a monovalent non-aromatic fused polycyclic group, a monovalentnon-aromatic fused heteropolycyclic group, —Si(Q₁₁)(Q₁₂)(Q₁₃),—N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂), —C(═O)(Q₁₁), —S(═O)₂(Q₁₁), and—P(═O)(Q₁₁)(Q₁₂);

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthiogroup, a monovalent non-aromatic fused polycyclic group, and amonovalent non-aromatic fused heteropolycyclic group;

a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthiogroup, a monovalent non-aromatic fused polycyclic group, and amonovalent non-aromatic fused heteropolycyclic group, each substitutedwith at least one selected from deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group,a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkylgroup, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, aC₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxygroup, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a C₁-C₆₀heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, a monovalentnon-aromatic fused polycyclic group, a monovalent non-aromatic fusedheteropolycyclic group, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂),—C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and —P(═O)(Q₂₁)(Q₂₂); and

—Si(Q₃₁)(Q₃₂)(Q₃₃), —N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁),—S(═O)₂(Q₃₁), and —P(═O)(Q₃₁)(Q₃₂),

wherein Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, and Q₃₁ to Q₃₃ may each independently beselected from hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, acyano group, a nitro group, an amidino group, a hydrazino group, ahydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkyl group, aC₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₁-C₆₀ heteroarylgroup, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthio group, amonovalent non-aromatic fused polycyclic group, a monovalentnon-aromatic fused heteropoly cyclic group, a C₁-C₆₀ alkyl groupsubstituted with at least one selected from deuterium, —F, and a cyanogroup, a C₆-C₆₀ aryl group substituted with at least one selected fromdeuterium, —F, and a cyano group, a biphenyl group, and a terphenylgroup.

As used herein, a substituent for a monovalent group, e.g., alkyl, mayalso be, independently, a substituent for a corresponding divalentgroup, e.g., alkylene.

The term “Ph” as used herein refers to a phenyl group, the term “Me” asused herein refers to a methyl group, the term “Et” as used hereinrefers to an ethyl group, the term “tert-Bu” or “Bu^(t)” as used hereinrefers to a tert-butyl group, and the term “OMe” as used herein refersto a methoxy group.

The term “biphenyl group” as used herein refers to “a phenyl groupsubstituted with a phenyl group”. In other words, the “biphenyl group”is a substituted phenyl group having a C₆-C₆₀ aryl group as asubstituent.

The term “terphenyl group” as used herein refers to “a phenyl groupsubstituted with a biphenyl group”. In other words, the “terphenylgroup” is a substituted phenyl group having, as a substituent, a C₆-C₆₀aryl group substituted with a C₆-C₆₀ aryl group.

* and *′ as used herein, unless defined otherwise, each refer to abinding site to a neighboring atom in a corresponding formula.

Hereinafter, a light-emitting device according to exemplary embodimentswill be described in detail with reference to Examples. The wording “Bwas used instead of A” used in describing Examples refers to that anidentical molar equivalent of B was used in place of A.

EXAMPLES Example 1

A 15 Ω/cm² (1,200 Å) ITO glass substrate (first electrode) from Corning,Inc. of Corning, New York was cut to the size of 50 mm×50 mm×0.7 mm,sonicated with isopropyl alcohol and pure water, each for 5 minutes, andthen cleaned by exposure to ultraviolet rays and ozone for 30 minutes.Then, the ITO glass substrate was provided to a vacuum depositionapparatus.

Compounds HT1, and 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane(F4-TCNQ), which was used as a p-dopant in amount of 2 wt %, werevacuum-deposited on the glass substrate to form a hole injection layerhaving a thickness of 100 Å, and then, HT1 was vacuum-deposited thereonto form a hole transport layer having a thickness of 700 Å.

The compound TCTA was vacuum-deposited on the hole transport layer toform an electron blocking layer having a thickness of 100 Å.

Compounds CBP and2,4-diphenyl-6-bis(12-phenylindolo)([2,3-a]carbazole-11-yl)-1,3,5-triazine(DIC-TRZ) (see the weight ratios of Table 1), which were used as hosts,and the compound PD26 (8 wt %), which was used as a dopant, wereco-deposited on the electron blocking layer to form an emission layerhaving a thickness of 200 Å.

DIC-TRZ was vacuum-deposited on the emission layer to form a holeblocking layer having a thickness of 100 Å.

The compounds ET1 and LiQ (weight ratio of 5:5) were vacuum-deposited onthe hole blocking layer to form an electron transport layer having athickness of 150 Å. LiF was vacuum-deposited on the electron transportlayer to form an electron injection layer having a thickness of 150 Å,and Al was vacuum-deposited on the electron transport layer to form asecond electrode having a thickness of 1000 Å, thereby completing themanufacture of an organic light-emitting device.

Examples 2 to 4 and Comparative Examples 1 to 3

Organic light-emitting devices were manufactured in the same manner asin Example 1, except that the structures of the emission layer and thecompound compositions of Table 1 were used. The first light-emittinglayer of Example 2 was formed so that the weight ratio of the hosts CBPand DIC-TRZ gradually changed from 10:0 to 2:8, and the secondlight-emitting layer of Example 2 was formed so that the weight ratio ofthe hosts CBP and DIC-TRZ gradually changed from 2:8 to 0:10.

Evaluation Example 2: Evaluation of Organic Light-Emitting Devices

The driving voltage, current efficiency, and lifespan (T95) of theorganic light-emitting devices manufactured according to Examples 1 to 4and Comparative Examples 1 to 3 were measured using a source-measureunit sold under the trade designation Keithley SMU 236 by Tektronix,Inc., of Beaverton, Oreg. and a luminance meter sold under the tradedesignation PR650, and the results are shown in Table 1. The lifespan isa measure of how long it took to reach 95% of the initial luminance.

TABLE 1 First emission Third emission Second emission Driving CurrentT₉₅ layer layer layer voltage efficiency (relative Host Dopant HostDopant Host Dopant (V) (cd/A) value) Example 1 CBP + PD26 — — CBP + PD264.5 21 207% DIC- DIC- TRZ TRZ (6:4) (3:7) Example 2 CBP + PD26 — — CBP+PD26 4.5 26 230% DIC- DIC- TRZ TRZ (CBP (CBP 100 wt % → 20 wt % → 20 wt%) 0 wt %) Example 3 CBP + PD26 CBP + PD26 CBP + PD26 4.3 25 246% DIC-DIC- DIC- TRZ TRZ TRZ (8:2) (5:5) (2:8) Example 4 CBP + PD26 + CBP +PD26 + 4.6 23 221% DIC- FD23 DIC- FD23 TRZ TRZ (6:4) (3:7) ComparativeCBP PD26 — — — — 5.1 14 100% Example 1 Comparative CBP + FD23 — — CBP +FD23 4.6 19 171% Example 2 DIC- DIC- TRZ TRZ (7:3) (3:7) ComparativeCBP + PD26 — — CBP + PD26 4.9 16 161% Example 3 DIC- DIC- TRZ TRZ (6:4)(8:2)

From Table 1, it can be seen that the organic light-emitting devices ofExamples 1 to 4 have a lower or equivalent driving voltage, highercurrent efficiency, and longer lifespan than those of ComparativeExample 1 to 3.

Although certain exemplary embodiments and implementations have beendescribed herein, other embodiments and modifications will be apparentfrom this description. Accordingly, the inventive concepts are notlimited to such embodiments, but rather to the broader scope of theappended claims and various obvious modifications and equivalentarrangements as would be apparent to a person of ordinary skill in theart.

What is claimed is:
 1. An organic light-emitting device comprising: afirst electrode; a second electrode facing the first electrode; and anorganic layer disposed between the first electrode and the secondelectrode and comprising a first emission layer and a second emissionlayer; wherein the first emission layer is located closer to the firstelectrode than the second emission layer and comprises a first holetransport host, a first electron transport host, and a firstphosphorescent dopant, and, in the first emission layer, an amount ofthe first hole transport host is greater than an amount of the firstelectron transport host, the second emission layer comprises a secondhole transport host, a second electron transport host, and a secondphosphorescent dopant, and, in the second emission layer, an amount ofthe second electron transport host is greater than an amount of thesecond hole transport host, and the first emission layer and the secondemission layer are configured to emit light of is substantially the samecolor.
 2. The organic light-emitting device of claim 1, wherein thefirst hole transport host and the second hole transport host are each,independently from one another, at least one of a compound representedby Formula 1:

the first electron transport host and the second electron transport hostare each, independently from one another, a compound represented byFormula 2:

wherein, m Formula 1 and Formula 2, Y₁ is a single bond, —O—, —S—,—C(R₂₄)(R₂₅)—, —N(R₂₄)—, —Si(R₂₄)(R₂₅)—, —C(═O)—, —S(═O)₂—, —(R₂₄)—,—P(R₂₄)—, or —P(═O)(R₂₄)(R₂₅)—; k1 is 0 or 1; CY₂₁ and CY₂₂ are each,independently from one another, a C₅-C₆₀ carbocyclic group or a C₁-C₆₀heterocyclic group; X₃₁ is N or C[(L₃₄)_(a34)-(R₃₁)], X₃₂ is N orC[(L₃₅)_(a35)-(R₃₂)], and X₃₃ is N or C[(L₃₆)_(a36)-(R₃₃)]; L₂₁ to L₂₃and L₃₁ to L₃₆ are each, independently from one another, a substitutedor unsubstituted C₃-C₁₀ cycloalkylene group, a substituted orunsubstituted C₁-C₁₀ is heterocycloalkylene group, a substituted orunsubstituted C₃-C₁₀ cycloalkenylene group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenylene group, a substituted orunsubstituted C₆-C₆₀ arylene group, a substituted or unsubstitutedC₁-C₆₀ heteroarylene group, a substituted or unsubstituted divalentnon-aromatic fused polycyclic group, or a substituted or unsubstituteddivalent non-aromatic fused heteropolycyclic group; a21 to a23 and a31to a36 are each, independently from one another, an integer from 0 to 5;Ar₂₁ to Ar₂₃ and Ar₃₁ to Ar₃₃ are each, independently from one another,a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkyl group, a substituted orunsubstituted C₃-C₁₀ cycloalkenyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀aryl group, a substituted or unsubstituted C₁-C₆₀ heteroaryl group, asubstituted or unsubstituted monovalent non-aromatic fused polycyclicgroup, or a substituted or unsubstituted monovalent non-aromatic fusedheteropolycyclic group; b21 to b23 and b31 to b33 are each,independently from one another, an integer from 1 to 8; R₂₁ to R₂₂, R₂₄to R₂₅, and R₃₁ to R₃₃ are each, independently from one another,hydrogen, deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group,a nitro group, an amidino group, a hydrazino group, a hydrazono group, asubstituted or unsubstituted C₁-C₆₀ alkyl group, a substituted orunsubstituted C₂-C₆₀ alkenyl group, a substituted or unsubstitutedC₂-C₆₀ alkynyl group, a substituted or unsubstituted C₁-C₆₀ alkoxygroup, a substituted or unsubstituted C₃-C₁₀ cycloalkyl group, asubstituted or unsubstituted C₁-C₁₀ heterocycloalkyl group, asubstituted or unsubstituted C₃-C₁₀ cycloalkenyl group, a substituted orunsubstituted C₁-C₁₀ heterocycloalkenyl group, a substituted orunsubstituted C₆-C₆₀ aryl group, a substituted or unsubstituted C₆-C₆₀aryloxy group, a substituted or unsubstituted C₆-C₆₀ arylthio group, asubstituted or unsubstituted C₁-C₆₀ heteroaryl group, a substituted orunsubstituted C₁-C₆₀ heteroaryloxy group, a substituted or unsubstitutedC₁-C₆₀ heteroarylthio group, a substituted or unsubstituted monovalentnon-aromatic fused polycyclic group, a substituted or unsubstitutedmonovalent non-aromatic fused heteropolycyclic group, —Si(Q₁)(Q₂)(Q₃),—N(Q₁)(Q₂), —B(Q₁)(Q₂), —C(═O)(Q₁), —S(═O)₂(Q₁) and —P(═O)(Q₁)(Q₂); c21and c22 are each, independently from one another, an integer from 1 to8; n21 and n22 are each, independently from one another, an integer from1 to 8; so at least two of Ar₂₁ to Ar₂₃ and R₂₁ to R₂₂ are optionallylinked to each other to form a substituted or unsubstituted C₅-C₆₀carbocyclic group or a substituted or unsubstituted C₁-C₆₀ heterocyclicgroup; at least two of Ar₃₁ to Ar₃₃ and R₃₁ to R₃₃ are optionally linkedto each other to form a substituted or unsubstituted C₅-C₆₀ carbocyclicgroup or a substituted or unsubstituted C₁-C₆₀ heterocyclic group; andat least one substituent of the substituted C₃-C₁₀ cycloalkylene group,the substituted C₁-C₁₀ heterocycloalkylene group, the substituted C₃-C₁₀cycloalkenylene group, the substituted C₁-C₁₀ heterocycloalkenylenegroup, the substituted C₆-C₆₀ arylene group, the substituted C₁-C₆₀heteroarylene group, the substituted divalent non-aromatic fusedpolycyclic group, the substituted divalent non-aromatic fusedheteropolycyclic group, the substituted C₅-C₆₀ carbocyclic group, thesubstituted C₁-C₆₀ heterocyclic group, the substituted C₁-C₆₀ alkylgroup, the substituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀alkynyl group, the substituted C₁-C₆₀ alkoxy group, the substitutedC₃-C₁₀ cycloalkyl group, the substituted C₁-C₁₀ heterocycloalkyl group,the substituted C₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀heterocycloalkenyl group, the substituted C₆-C₆₀ aryl group, thesubstituted C₆-C₆₀ aryloxy group, the substituted C₆—C₆₀ arylthio group,the substituted C₁-C₆₀ heteroaryl group, the substituted C₁-C₆₀heteroaryloxy group, the substituted C₁-C₆₀ heteroarylthio group, thesubstituted monovalent non-aromatic fused polycyclic group, and thesubstituted monovalent non-aromatic fused heteropolycyclic group is:deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀alkyl group, a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and aC₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group, aC₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group, each, independentlyfrom one another, substituted with at least one of deuterium, —F, —Cl,—Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₃-C₁₀ cycloalkyl group,a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic fused polycyclic group, a monovalent non-aromatic fusedheteropolycyclic group, —Si(Q₁₁)(Q₁₂)(Q₁₃), —N(Q₁₁)(Q₁₂), —B(Q₁₁)(Q₁₂),—C(═O)(Q₁₁), —S(═O)₂(Q₁₁), and —P(═O)(Q₁₁)(Q₁₂); a C₃-C₁₀ cycloalkylgroup, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, aC₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxygroup, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic fused polycyclic group, and a monovalent non-aromatic fusedheteropolycyclic group, each, independently from one another, optionallysubstituted with at least one of deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group,a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, a C₃-C₁₀ cycloalkylgroup, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, aC₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxygroup, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic fused polycyclic group, a monovalent non-aromatic fusedheteropolycyclic group, —Si(Q₂₁)(Q₂₂)(Q₂₃), —N(Q₂₁)(Q₂₂), —B(Q₂₁)(Q₂₂),—C(═O)(Q₂₁), —S(═O)₂(Q₂₁), and —P(═O)(Q₂₁)(Q₂₂); and —Si(Q₃₁)(Q₃₂)(Q₃₃),—N(Q₃₁)(Q₃₂), —B(Q₃₁)(Q₃₂), —C(═O)(Q₃₁), —S(═O)₂(Q₃₁), and—P(═O)(Q₃₁)(Q₃₂); wherein Q₁ to Q₃, Q₁₁ to Q₁₃, Q₂₁ to Q₂₃, and Q₃₁ toQ₃₃ are each, independently from one another, hydrogen, deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, aC₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, aC₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₁-C₆₀ heteroaryl group, a monovalent non-aromatic fusedpolycyclic group, a monovalent non-aromatic fused heteropolycyclicgroup, a biphenyl group, and a terphenyl group.
 3. The organiclight-emitting device of claim 1, wherein the first hole transport hostand the second hole transport host are substantially identical to eachother.
 4. The organic light-emitting device of claim 1, wherein thefirst electron transport host and the second electron transport host aresubstantially identical to each other.
 5. The organic light-emittingdevice of claim 1, wherein the first emission layer and the secondemission layer each configured to emit blue light having a maximumemission wavelength of about 400 nm to about 500 nm.
 6. The organiclight-emitting device of claim 1, wherein the first phosphorescentdopant and the second phosphorescent dopant are substantially identicalto each other.
 7. The organic light-emitting device of claim 1, whereinat least one of the first emission layer and the second emission layerfurther comprises at least one of a fluorescence dopant and a delayedfluorescence dopant.
 8. The organic light-emitting device of claim 1,wherein the organic layer further comprises a third emission layerdisposed between the first emission layer and the second emission layer,and the third emission layer includes a third hole transport host, athird electron transport host, and a third phosphorescent dopant.
 9. Theorganic light-emitting device of claim 8, wherein the amount of thefirst hole transport host in the first emission layer is greater than anamount of the third hole transport host in the third emission layer, andthe amount of the third hole transport host in the third emission layeris greater than the amount of the second hole transport host in thesecond emission layer.
 10. The organic light-emitting device of claim 8,wherein the amount of the second electron transport host in the secondemission layer is greater than an amount of the third electron transporthost in the third emission layer, and the amount of the third electrontransport host in the third emission layer is greater than the amount ofthe first electron transport host in the first emission layer.
 11. Theorganic light-emitting device of claim 8, wherein the third holetransport host and the third electron transport host of the thirdemission layer have a weight ratio in the range of about 4:6 to about6:4.
 12. The organic light-emitting device of claim 8, wherein the firsthole transport host, the second hole transport host, and the third holetransport host are substantially identical to each other.
 13. Theorganic light-emitting device of claim 8, wherein the first electrontransport host, the second electron transport host, and the thirdelectron transport host are substantially identical to each other. 14.The organic light-emitting device of claim 8, wherein the firstphosphorescent dopant, the second phosphorescent dopant, and the thirdphosphorescent dopant are substantially identical to each other.
 15. Theorganic light-emitting device of claim 1, wherein the first electrode isan anode; the second electrode is a cathode; and the organic layerfurther comprises a hole transport region disposed between the firstelectrode and an emission layer and an electron transport regiondisposed between the emission layer and the second electrode.
 16. Theorganic light-emitting device of claim 15, wherein the hole transportregion comprises at least one of a hole injection layer, a holetransport layer, a buffer layer, an emission auxiliary layer, and anelectron blocking layer, and the electron transport region comprises atleast one of a hole blocking layer, a buffer layer, an electron controllayer, an electron transport layer, and an electron injection layer. 17.The organic light-emitting device of claim 15, wherein the holetransport region comprises a p-dopant having a lowest unoccupiedmolecular orbital energy level of less than about −3.5 eV.
 18. Theorganic light-emitting device of claim 15, wherein: the electrontransport region comprises a hole blocking layer including a holeblocking material; the hole blocking layer directly contacts the secondemission layer; and the hole blocking material is substantially the sameas the second electron transport host.
 19. The organic light-emittingdevice of claim 15, wherein the electron transport region comprises ametal-containing material.
 20. An organic light-emitting devicecomprising: a first electrode; a second electrode facing the firstelectrode; and an organic layer disposed between the first electrode andthe second electrode and including an emission layer, having a firstemission area and a second emission area; wherein, in the emissionlayer, the first emission area is located closer to the first electrodethan the second emission area; each of the first emission area and thesecond emission area includes a hole transport host, an electrontransport host, and a phosphorescent dopant; an amount of the holetransport host in the first emission area is greater than an amount ofthe electron transport host in the first emission area; an amount of theelectron transport host in the second emission area is greater than anamount of the hole transport host in the second emission area; and thephosphorescent dopant is an organometallic compound represented byFormula 4 or is 5:

wherein, in Formulae 4 and 5, M₄ and M₅ are each, independently from oneanother, platinum (Pt), palladium (Pd), copper (Cu), silver (Ag), gold(Au), rhodium (Rh), iridium (Ir), ruthenium (Ru), osmium (Os), titanium(Ti), zirconium (Zr), hafnium (Hf), europium (Eu), terbium (Tb), orthulium (Tm); n51 is an integer from 1 to 3; Ln₅₂ is an organic ligand,and n52 is an integer from 0 to 2; Y₄₁ to Y₄₄, Y₅₁ and Y₅₂ are each,independently from one another, N or C; A₄₁ to A₄₄, A₅₁ and A₅₂ areeach, independently from one another, a C₅-C₆₀ carbocyclic group, or aC₁-C₆₀ heterocyclic group; at least one of A₄₁ to A₄₄ is a carbene ring,and at least one of A₅₁ and A₅₂ is a carbene ring; T₄₁ to T₄₄, T_(51J)and T₅₂ are each, independently from one another, a single bond, *—O—*′,or *—S—*′; L₄₁ to L₄₄ and L₅₁ are each, independently from one another,of a single bond, *—O—*′, *—S—*′, *—C(R₄₅)(R₄₆)—*′, *—C(R₄₅)=*′,*═C(R₄₅)—*′, *—C(R₄₅)═C(R₄₆)—*′, *—C(═O)—*′, *—C(═S)—*′, *—C≡C—*′,*—B(R₄₅)—*′, *—N(R₄₅)—*′, *—P(R₄₅)—*′, *—Si(R₄₅)(R₄₆)—*′,*—P(R₄₅)(R₄₆)—*′, or *—Ge(R₄₅)(R₄₆)—*′; m41 to m44 and m51 are each,independently from one another, an integer from 0 to 3, R₄₁ to R₄₆, R₅₁,and R₅₂ are each, independently from one another, hydrogen, deuterium,—F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, anamidino group, a hydrazine group, a hydrazone group, a substituted orunsubstituted C₁-C₆₀ alkyl group, a substituted or unsubstituted C₂-C₆₀alkenyl group, a substituted or unsubstituted C₂-C₆₀ alkynyl group, asubstituted or unsubstituted C₁-C₆n alkoxy group, a substituted orunsubstituted C₃-C₁₀ cycloalkyl group, a substituted or unsubstitutedC₁-C₁₀ heterocycloalkyl group, a substituted or unsubstituted C₃-C₁₀cycloalkenyl group, a substituted or unsubstituted C₁-C₁₀heterocycloalkenyl group, a substituted or unsubstituted C₆-C₆₀ arylgroup, a substituted or unsubstituted C₆-C₆₀ aryloxy group, asubstituted or unsubstituted C₆-C₆₀ arylthio group, a substituted orunsubstituted C₁-C₆₀ heteroaryl group, a substituted or unsubstitutedmonovalent non-aromatic fused polycyclic group, a substituted orunsubstituted monovalent non-aromatic fused heteropolycyclic group,—Si(Q₄₁)(Q₄₂)(Q₄₃), —N(Q₄₁)(Q₄₂), —B(Q₄₁)(Q₄₂), —C(═O)(Q₄₁),—S(═O)₂(Q₄₁), or —P(═O)(Q₄₁)(Q₄₂); regarding a pair of R₄₅ and R₄₁, apair of R₄₅ and R₄₂, a pair of R₄₅ and R₄₃, or a pair of R₄₅ and R₄₄,components of each pair are optionally linked to form a substituted orunsubstituted C₅-C₆₀ carbocyclic group or a substituted or unsubstitutedC₁-C₆₀ heterocyclic group; b41 to b44, b51 and b52 are each,independently from one another, an integer from 1 to 8; * and *′ eachindicate a binding site to a neighboring atom; and at least onesubstituent of the substituted C₅-C₆₀ carbocyclic group, the substitutedC₁-C₆₀ heterocyclic group, the substituted C₁-C₆₀ alkyl group, thesubstituted C₂-C₆₀ alkenyl group, the substituted C₂-C₆₀ alkynyl group,the substituted C₁-C₆₀ alkoxy group, the substituted C₃-C₁₀ cycloalkylgroup, the substituted C₁-C₁₀ heterocycloalkyl group, the substitutedC₃-C₁₀ cycloalkenyl group, the substituted C₁-C₁₀ heterocycloalkenylgroup, the substituted C₆-C₆₀ aryl group, the substituted C₆-C₆₀ aryloxygroup, the substituted C₆-C₆₀ arylthio group, the substituted C₁-C₆₀heteroaryl group, the substituted monovalent non-aromatic fusedpolycyclic group, and the substituted monovalent non-aromatic fusedheteropolycyclic group is: deuterium, —F, —Cl, —Br, —I, a hydroxylgroup, a cyano group, a nitro group, an amidino group, a hydrazinogroup, a hydrazono group, a C₁-C₆₀ alkyl group, a C₂-C₆₀ alkenyl group,a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxy group; a C₁-C₆₀ alkyl group,a C₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, and a C₁-C₆₀ alkoxygroup, each substituted with at least one of deuterium, —F, —Cl, —Br,—I, a hydroxyl group, a cyano group, a nitro group, an amidino group, ahydrazino group, a hydrazono group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, aC₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic fused polycyclic group, a monovalent non-aromatic fusedheteropolycyclic group, —Si(Q₅₁)(Q₅₂)(Q₅₃), —N(Q₅₁)(Q₅₂), —B(Q₅₁)(Q₅₂),—C(═O)(Q₅₁), —S(═O)₂(Q₅₁) and —P(═O)(Q₅₁)(Q₅₂); a C₃-C₁₀ cycloalkylgroup, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀ cycloalkenyl group, aC₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ aryl group, a C₆-C₆₀ aryloxygroup, a C₆-C₆₀ arylthio group, a C₁-C₆₀ heteroaryl group, a monovalentnon-aromatic fused polycyclic group, and a monovalent non-aromatic fusedheteropolycyclic group, each optionally substituted with at so least oneof deuterium, —F, —Cl, —Br, —I, a hydroxyl group, a cyano group, a nitrogroup, an amidino group, a hydrazino group, a hydrazono group, a C₁-C₆₀alkyl group, a C₁-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀alkoxy group, a C₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkylgroup, a C₃-C₁₀ cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, aC₆-C₆₀ aryl group, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, aC₁-C₆₀ heteroaryl group, a monovalent non-aromatic fused polycyclicgroup, a monovalent non-aromatic fused heteropolycyclic group,—Si(Q₆₁)(Q₆₂)(Q₆₃), —N(Q₆₁)(Q₆₂), —B(Q₆₁)(Q₆₂), —C(═O)(Q₆₁),—S(═O)₂(Q₆₁), and —P(═O)(Q₆₁)(Q₆₂); and —Si(Q₇₁)(Q₇₂)(Q₇₃),—N(Q₇₁)(Q₇₂), —B(Q₇₁)(Q₇₂), —C(═O)(Q₇₁), —S(═O)₂(Q₇₁) and—P(═O)(Q₇₁)(Q₇₂), wherein Q₄₁ to Q₄₃, Q₅₁ to Q₅₃, Q₆₁ to Q₆₃, and Q₇₁ toQ₇₃ are each, independently from one another, hydrogen, deuterium, —F,—Cl, —Br, —I, a hydroxyl group, a cyano group, a nitro group, an amidinogroup, a hydrazino group, a hydrazono group, a C₁-C₆₀ alkyl group, aC₂-C₆₀ alkenyl group, a C₂-C₆₀ alkynyl group, a C₁-C₆₀ alkoxy group, aC₃-C₁₀ cycloalkyl group, a C₁-C₁₀ heterocycloalkyl group, a C₃-C₁₀cycloalkenyl group, a C₁-C₁₀ heterocycloalkenyl group, a C₆-C₆₀ arylgroup, a C₆-C₆₀ aryloxy group, a C₆-C₆₀ arylthio group, a C₁-C₆₀heteroaryl group, a C₁-C₆₀ heteroaryloxy group, a C₁-C₆₀ heteroarylthiogroup, monovalent non-aromatic fused polycyclic group, monovalentnon-aromatic fused heteropolycyclic group; a C₁-C₆₀ alkyl groupoptionally substituted with at least one of deuterium, —F, and a cyanogroup; a C₆-C₆₀ aryl group optionally substituted with at least one ofdeuterium, —F, and a cyano group; a biphenyl group, or a terphenylgroup.
 21. The organic light-emitting device of claim 20, wherein theemission layer is configured to emit blue light having a maximumemission wavelength of about 400 nm to about 500 nm.
 22. The organiclight-emitting device of claim 20, wherein an amount of the holetransport host in the emission layer gradually decreases from the firstemission area toward the second emission area, and an amount of theelectron transport host in the emission layer gradually increases fromthe first emission area toward the second emission area.
 23. The organiclight-emitting device of claim 20, wherein the first electrode is ananode, the second electrode is a cathode, the organic layer furthercomprises a hole transport region disposed between the first electrodeand the emission layer and an electron transport region disposed betweenthe emission layer and the second electrode, the hole transport regioncomprises at least one of a hole injection layer, a hole transportlayer, a buffer layer, an emission auxiliary layer, and an electronblocking layer, and the electron transport region comprises at least oneof a hole blocking layer, a buffer layer, an electron control layer, anelectron transport layer, and an electron injection layer.
 24. Theorganic light-emitting device of claim 23, wherein the hole transportregion comprises a p-dopant having a lowest unoccupied molecular orbitalenergy level of less than about −3.5 eV.
 25. The organic light-emittingdevice of claim 23, wherein the electron transport region comprises thehole blocking layer including a hole blocking material; the holeblocking layer directly contacts the emission layer; and the holeblocking material is substantially identical to the hole transport host.26. The organic light-emitting device of claim 23, wherein the electrontransport region comprises a metal-containing material.
 27. An apparatuscomprising: a thin-film transistor including a source electrode, a drainelectrode, and an activation layer; and the organic light-emittingdevice of claim 1; wherein the first electrode of the organiclight-emitting device is electrically connected with one of the sourceelectrode and the drain electrode of the thin-film transistor.